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[InstCombine] Canonicalise SextADD + GEP #69581

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Merged
merged 1 commit into from
Nov 29, 2023
Merged

[InstCombine] Canonicalise SextADD + GEP #69581

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22 changes: 19 additions & 3 deletions llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2436,15 +2436,31 @@ Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) {
if (match(GEP.getOperand(1),
m_OneUse(m_Add(m_Value(Idx1), m_Value(Idx2))))) {
// %idx = add i64 %idx1, %idx2
// %gep = getelementptr i32, i32* %ptr, i64 %idx
// %gep = getelementptr i32, ptr %ptr, i64 %idx
// as:
// %newptr = getelementptr i32, i32* %ptr, i64 %idx1
// %newgep = getelementptr i32, i32* %newptr, i64 %idx2
// %newptr = getelementptr i32, ptr %ptr, i64 %idx1
// %newgep = getelementptr i32, ptr %newptr, i64 %idx2
auto *NewPtr = Builder.CreateGEP(GEP.getResultElementType(),
GEP.getPointerOperand(), Idx1);
return GetElementPtrInst::Create(GEP.getResultElementType(), NewPtr,
Idx2);
}
ConstantInt *C;
if (match(GEP.getOperand(1), m_OneUse(m_SExt(m_OneUse(m_NSWAdd(
m_Value(Idx1), m_ConstantInt(C))))))) {
// %add = add nsw i32 %idx1, idx2
// %sidx = sext i32 %add to i64
// %gep = getelementptr i32, ptr %ptr, i64 %sidx
// as:
// %newptr = getelementptr i32, ptr %ptr, i32 %idx1
// %newgep = getelementptr i32, ptr %newptr, i32 idx2
auto *NewPtr = Builder.CreateGEP(
GEP.getResultElementType(), GEP.getPointerOperand(),
Builder.CreateSExt(Idx1, GEP.getOperand(1)->getType()));
return GetElementPtrInst::Create(
GEP.getResultElementType(), NewPtr,
Builder.CreateSExt(C, GEP.getOperand(1)->getType()));
}
}

if (!GEP.isInBounds()) {
Expand Down
74 changes: 74 additions & 0 deletions llvm/test/Transforms/InstCombine/array.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,74 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
; RUN: opt < %s -passes=instcombine -S | FileCheck %s

define void @test(ptr %ptr, i32 %a, i32 %b) {
; CHECK-LABEL: define void @test(
; CHECK-SAME: ptr [[PTR:%.*]], i32 [[A:%.*]], i32 [[B:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = sext i32 [[A]] to i64
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr i32, ptr [[PTR]], i64 [[TMP0]]
; CHECK-NEXT: [[GEP:%.*]] = getelementptr i32, ptr [[TMP1]], i64 10
; CHECK-NEXT: store i32 [[B]], ptr [[GEP]], align 4
; CHECK-NEXT: ret void
;
entry:
%add = add nsw i32 %a, 10
%idx = sext i32 %add to i64
%gep = getelementptr inbounds i32, ptr %ptr, i64 %idx
store i32 %b, ptr %gep
ret void
}

define i32 @test_add_res_moreoneuse(ptr %ptr, i32 %a, i32 %b) {
; CHECK-LABEL: define i32 @test_add_res_moreoneuse(
; CHECK-SAME: ptr [[PTR:%.*]], i32 [[A:%.*]], i32 [[B:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[A]], 5
; CHECK-NEXT: [[IDX:%.*]] = sext i32 [[ADD]] to i64
; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 [[IDX]]
; CHECK-NEXT: store i32 [[B]], ptr [[GEP]], align 4
; CHECK-NEXT: ret i32 [[ADD]]
;
entry:
%add = add nsw i32 %a, 5
%idx = sext i32 %add to i64
%gep = getelementptr inbounds i32, ptr %ptr, i64 %idx
store i32 %b, ptr %gep
ret i32 %add
}

define void @test_addop_nonsw_flag(ptr %ptr, i32 %a, i32 %b) {
; CHECK-LABEL: define void @test_addop_nonsw_flag(
; CHECK-SAME: ptr [[PTR:%.*]], i32 [[A:%.*]], i32 [[B:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[ADD:%.*]] = add i32 [[A]], 10
; CHECK-NEXT: [[IDX:%.*]] = sext i32 [[ADD]] to i64
; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 [[IDX]]
; CHECK-NEXT: store i32 [[B]], ptr [[GEP]], align 4
; CHECK-NEXT: ret void
;
entry:
%add = add i32 %a, 10
%idx = sext i32 %add to i64
%gep = getelementptr inbounds i32, ptr %ptr, i64 %idx
store i32 %b, ptr %gep
ret void
}

define void @test_add_op2_not_constant(ptr %ptr, i32 %a, i32 %b) {
; CHECK-LABEL: define void @test_add_op2_not_constant(
; CHECK-SAME: ptr [[PTR:%.*]], i32 [[A:%.*]], i32 [[B:%.*]]) {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[ADD:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: [[IDX:%.*]] = sext i32 [[ADD]] to i64
; CHECK-NEXT: [[GEP:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 [[IDX]]
; CHECK-NEXT: store i32 [[B]], ptr [[GEP]], align 4
; CHECK-NEXT: ret void
;
entry:
%add = add i32 %a, %b
%idx = sext i32 %add to i64
%gep = getelementptr inbounds i32, ptr %ptr, i64 %idx
store i32 %b, ptr %gep
ret void
}