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[X86] Add test coverage for PR33879 (Issue llvm#33226)
Ensure we only use the eflags results from shift instructions when it won't cause stalls shift by variable causes stalls as it has to preserve eflags when the shift amount was zero, so we're better off using a separate test
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‎llvm/test/CodeGen/X86/shift-eflags.ll

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; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
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; RUN: llc < %s -mtriple=x86_64-- | FileCheck %s
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; PR33879 - use shift eflags result when it won't cause stalls
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; ashr by constant - use sarl eflags result
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define i32 @ashr_const(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_const:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edx, %eax
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; CHECK-NEXT: sarl $14, %edi
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; CHECK-NEXT: cmovnel %ecx, %eax
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; CHECK-NEXT: retq
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%s = ashr i32 %a0, 14
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; lshr by constant - simplify to test
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define i32 @lshr_const(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: lshr_const:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edx, %eax
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; CHECK-NEXT: testl $-16384, %edi # imm = 0xC000
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; CHECK-NEXT: cmovnel %ecx, %eax
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; CHECK-NEXT: retq
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%s = lshr i32 %a0, 14
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; shl by constant - simplify to test
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define i32 @shl_const(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: shl_const:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edx, %eax
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; CHECK-NEXT: testl $262143, %edi # imm = 0x3FFFF
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; CHECK-NEXT: cmovnel %ecx, %eax
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; CHECK-NEXT: retq
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%s = shl i32 %a0, 14
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; ashr by constant and using shift result - use sarl eflags result
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define i32 @ashr_const_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_const_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: sarl $14, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = ashr i32 %a0, 14
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; lshr by constant and using shift result - use shrl eflags result
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define i32 @lshr_const_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: lshr_const_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: shrl $14, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = lshr i32 %a0, 14
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; lshr by constant and using result - use shll eflags result
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define i32 @shl_const_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: shl_const_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: shll $14, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = shl i32 %a0, 14
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; ashr by 1 - use sarl eflags result
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define i32 @ashr_const1(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_const1:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edx, %eax
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; CHECK-NEXT: sarl %edi
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; CHECK-NEXT: cmovnel %ecx, %eax
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; CHECK-NEXT: retq
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%s = ashr i32 %a0, 1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; lshr by 1 - simplify to test
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define i32 @lshr_const1(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: lshr_const1:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edx, %eax
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; CHECK-NEXT: testl $-2, %edi
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; CHECK-NEXT: cmovnel %ecx, %eax
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; CHECK-NEXT: retq
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%s = lshr i32 %a0, 1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; shl by 1 - simplify to test
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define i32 @shl_const1(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: shl_const1:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edx, %eax
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; CHECK-NEXT: testl $2147483647, %edi # imm = 0x7FFFFFFF
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; CHECK-NEXT: cmovnel %ecx, %eax
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; CHECK-NEXT: retq
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%s = shl i32 %a0, 1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; ashr by 1 and using shift result - use sarl eflags result
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define i32 @ashr_const1_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_const1_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: sarl %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = ashr i32 %a0, 1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; lshr by 1 and using shift result - use shrl eflags result
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define i32 @lshr_const1_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: lshr_const1_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: shrl %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = lshr i32 %a0, 1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; lshr by 1 and using result - use addl eflags result
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define i32 @shl_const1_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: shl_const1_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: addl %edi, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = shl i32 %a0, 1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; ashr by variable - use seperate test
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define i32 @ashr_var(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_var:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %ecx, %eax
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: sarl %cl, %edi
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovel %edx, %eax
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; CHECK-NEXT: retq
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%s = ashr i32 %a0, %a1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; lshr by variable - use seperate test
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define i32 @lshr_var(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: lshr_var:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %ecx, %eax
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shrl %cl, %edi
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovel %edx, %eax
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; CHECK-NEXT: retq
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%s = lshr i32 %a0, %a1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; shl by variable - use seperate test
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define i32 @shl_var(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: shl_var:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %ecx, %eax
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shll %cl, %edi
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovel %edx, %eax
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; CHECK-NEXT: retq
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%s = shl i32 %a0, %a1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; ashr by variable and using result - use seperate test
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define i32 @ashr_var_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_var_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: sarl %cl, %eax
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; CHECK-NEXT: testl %eax, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = ashr i32 %a0, %a1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; lshr by variable and using result - use seperate test
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define i32 @lshr_var_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: lshr_var_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shrl %cl, %eax
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; CHECK-NEXT: testl %eax, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = lshr i32 %a0, %a1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; shl by variable and using result - use seperate test
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define i32 @shl_var_self_select(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: shl_var_self_select:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shll %cl, %eax
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; CHECK-NEXT: testl %eax, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%s = shl i32 %a0, %a1
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; ashr by non-zero variable - use seperate test
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define i32 @ashr_var_amt_never_zero(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_var_amt_never_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %ecx, %eax
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: orb $1, %cl
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: sarl %cl, %edi
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovel %edx, %eax
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; CHECK-NEXT: retq
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%a = or i32 %a1, 1
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%s = ashr i32 %a0, %a
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; lshr by non-zero variable - use seperate test
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define i32 @lshr_var_amt_never_zero(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
297+
; CHECK-LABEL: lshr_var_amt_never_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %ecx, %eax
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: orb $1, %cl
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shrl %cl, %edi
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovel %edx, %eax
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; CHECK-NEXT: retq
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%a = or i32 %a1, 1
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%s = lshr i32 %a0, %a
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; shl by non-zero variable - use seperate test
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define i32 @shl_var_amt_never_zero(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: shl_var_amt_never_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %ecx, %eax
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: orb $1, %cl
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shll %cl, %edi
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovel %edx, %eax
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; CHECK-NEXT: retq
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%a = or i32 %a1, 1
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%s = shl i32 %a0, %a
328+
%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %a2, i32 %a3
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ret i32 %r
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}
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; ashr by non-zero variable and using result - use seperate test
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define i32 @ashr_var_self_select_amt_never_zero(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: ashr_var_self_select_amt_never_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: orb $1, %cl
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shrl %cl, %eax
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; CHECK-NEXT: testl %eax, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
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%a = or i32 %a1, 1
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%s = lshr i32 %a0, %a
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}
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; lshr by non-zero variable and using result - use seperate test
353+
define i32 @lshr_var_self_select_amt_never_zero(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
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; CHECK-LABEL: lshr_var_self_select_amt_never_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: orb $1, %cl
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shrl %cl, %eax
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; CHECK-NEXT: testl %eax, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
364+
%a = or i32 %a1, 1
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%s = lshr i32 %a0, %a
366+
%c = icmp eq i32 %s, 0
367+
%r = select i1 %c, i32 %s, i32 %a2
368+
ret i32 %r
369+
}
370+
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; shl by non-zero variable and using result - use seperate test
372+
define i32 @shl_var_self_select_amt_never_zero(i32 %a0, i32 %a1, i32 %a2, i32 %a3) {
373+
; CHECK-LABEL: shl_var_self_select_amt_never_zero:
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; CHECK: # %bb.0:
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; CHECK-NEXT: movl %esi, %ecx
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: orb $1, %cl
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; CHECK-NEXT: # kill: def $cl killed $cl killed $ecx
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; CHECK-NEXT: shrl %cl, %eax
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; CHECK-NEXT: testl %eax, %eax
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; CHECK-NEXT: cmovnel %edx, %eax
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; CHECK-NEXT: retq
383+
%a = or i32 %a1, 1
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%s = lshr i32 %a0, %a
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%c = icmp eq i32 %s, 0
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%r = select i1 %c, i32 %s, i32 %a2
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ret i32 %r
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}

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