[X86] Add test for foldable add of mul (NFC)

Author: nikic

llvm/test/CodeGen/X86/add-of-mul.ll

@@ -0,0 +1,63 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 2
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+define i32 @test_scalar(i32 %x) {
+; CHECK-LABEL: test_scalar:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    leal (%rdi,%rdi,2), %eax
+; CHECK-NEXT:    addl %edi, %eax
+; CHECK-NEXT:    retq
+  %mul = mul i32 %x, 3
+  %add = add i32 %mul, %x
+  ret i32 %add
+}
+
+define <4 x i32> @test_vector(<4 x i32> %x) {
+; CHECK-LABEL: test_vector:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    paddd %xmm0, %xmm0
+; CHECK-NEXT:    paddd %xmm0, %xmm0
+; CHECK-NEXT:    retq
+  %mul = mul <4 x i32> %x, <i32 3, i32 3, i32 3, i32 3>
+  %add = add <4 x i32> %mul, %x
+  ret <4 x i32> %add
+}
+
+define ptr @test_ptr(ptr %p) {
+; CHECK-LABEL: test_ptr:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    leaq (%rdi,%rdi,2), %rax
+; CHECK-NEXT:    addq %rdi, %rax
+; CHECK-NEXT:    retq
+  %addr = ptrtoint ptr %p to i64
+  %mul = mul i64 %addr, 3
+  %res = getelementptr i8, ptr %p, i64 %mul
+  ret ptr %res
+}
+
+define i32 @test_extra_use(i32 %x, ptr %p) {
+; CHECK-LABEL: test_extra_use:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    leal (%rdi,%rdi,2), %eax
+; CHECK-NEXT:    movl %eax, (%rsi)
+; CHECK-NEXT:    addl %edi, %eax
+; CHECK-NEXT:    retq
+  %mul = mul i32 %x, 3
+  store i32 %mul, ptr %p
+  %add = add i32 %mul, %x
+  ret i32 %add
+}
+
+define i32 @test_different_operand(i32 %x, i32 %y) {
+; CHECK-LABEL: test_different_operand:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    # kill: def $edi killed $edi def $rdi
+; CHECK-NEXT:    leal (%rdi,%rdi,2), %eax
+; CHECK-NEXT:    addl %esi, %eax
+; CHECK-NEXT:    retq
+  %mul = mul i32 %x, 3
+  %add = add i32 %mul, %y
+  ret i32 %add
+}