[llvm] [InstCombine] ptrmask of gep for dynamic pointer aligment (PR #80002)
Jon Chesterfield via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 7 09:08:09 PST 2024
https://github.com/JonChesterfield updated https://github.com/llvm/llvm-project/pull/80002
>From 8b2b14f2d25957422958e8d3c5664246c7f85f0f Mon Sep 17 00:00:00 2001
From: Jon Chesterfield <jonathanchesterfield at gmail.com>
Date: Tue, 30 Jan 2024 13:04:26 +0000
Subject: [PATCH] [InstCombine] ptrmask of gep for dynamic pointer aligment
---
.../InstCombineSimplifyDemanded.cpp | 38 ++++
llvm/test/Transforms/InstCombine/ptrmask.ll | 164 +++++++++++++++++-
2 files changed, 198 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 1b963a7de4a8ae..c691c8b1c55b30 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -997,6 +997,44 @@ Value *InstCombinerImpl::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
I, 1, (DemandedMask & ~LHSKnown.Zero).zextOrTrunc(MaskWidth)))
return I;
+ // Combine:
+ // (ptrmask (getelementptr i8, ptr p, imm i), imm mask)
+ // -> (ptrmask (getelementptr i8, ptr p, imm (i & mask)), imm mask)
+ // where only the low bits known to be zero in the pointer are changed
+ Value *InnerPtr;
+ uint64_t GEPIndex;
+ uint64_t PtrMaskImmediate;
+ if (match(I, m_Intrinsic<Intrinsic::ptrmask>(
+ m_PtrAdd(m_Value(InnerPtr), m_ConstantInt(GEPIndex)),
+ m_ConstantInt(PtrMaskImmediate)))) {
+
+ LHSKnown = computeKnownBits(InnerPtr, Depth + 1, I);
+ if (!LHSKnown.isZero()) {
+ const unsigned trailingZeros = LHSKnown.countMinTrailingZeros();
+ uint64_t PointerAlignBits = (uint64_t(1) << trailingZeros) - 1;
+
+ uint64_t HighBitsGEPIndex = GEPIndex & ~PointerAlignBits;
+ uint64_t MaskedLowBitsGEPIndex =
+ GEPIndex & PointerAlignBits & PtrMaskImmediate;
+
+ uint64_t MaskedGEPIndex = HighBitsGEPIndex | MaskedLowBitsGEPIndex;
+
+ if (MaskedGEPIndex != GEPIndex) {
+ auto *GEP = cast<GetElementPtrInst>(II->getArgOperand(0));
+ Builder.SetInsertPoint(I);
+ Type *GEPIndexType =
+ DL.getIndexType(GEP->getPointerOperand()->getType());
+ Value *MaskedGEP = Builder.CreateGEP(
+ GEP->getSourceElementType(), InnerPtr,
+ ConstantInt::get(GEPIndexType, MaskedGEPIndex),
+ GEP->getName(), GEP->isInBounds());
+
+ replaceOperand(*I, 0, MaskedGEP);
+ return I;
+ }
+ }
+ }
+
break;
}
diff --git a/llvm/test/Transforms/InstCombine/ptrmask.ll b/llvm/test/Transforms/InstCombine/ptrmask.ll
index afeb5d5251d0f4..4631b81cd1ce1f 100644
--- a/llvm/test/Transforms/InstCombine/ptrmask.ll
+++ b/llvm/test/Transforms/InstCombine/ptrmask.ll
@@ -80,12 +80,12 @@ define ptr addrspace(1) @ptrmask_combine_consecutive_preserve_attrs_todo2(ptr ad
define ptr @ptrmask_combine_add_nonnull(ptr %p) {
; CHECK-LABEL: define ptr @ptrmask_combine_add_nonnull
; CHECK-SAME: (ptr [[P:%.*]]) {
-; CHECK-NEXT: [[PM0:%.*]] = call align 64 ptr @llvm.ptrmask.p0.i64(ptr [[P]], i64 -64)
-; CHECK-NEXT: [[PGEP:%.*]] = getelementptr i8, ptr [[PM0]], i64 33
-; CHECK-NEXT: [[R:%.*]] = call nonnull align 32 ptr @llvm.ptrmask.p0.i64(ptr [[PGEP]], i64 -32)
+; CHECK-NEXT: [[PM0:%.*]] = call align 4 ptr @llvm.ptrmask.p0.i64(ptr [[P]], i64 -60)
+; CHECK-NEXT: [[PGEP1:%.*]] = getelementptr i8, ptr [[PM0]], i64 32
+; CHECK-NEXT: [[R:%.*]] = call nonnull align 32 ptr @llvm.ptrmask.p0.i64(ptr [[PGEP1]], i64 -32)
; CHECK-NEXT: ret ptr [[R]]
;
- %pm0 = call ptr @llvm.ptrmask.p0.i64(ptr %p, i64 -64)
+ %pm0 = call ptr @llvm.ptrmask.p0.i64(ptr %p, i64 -60)
%pgep = getelementptr i8, ptr %pm0, i64 33
%r = call ptr @llvm.ptrmask.p0.i64(ptr %pgep, i64 -16)
ret ptr %r
@@ -287,6 +287,162 @@ define ptr addrspace(1) @ptrmask_maintain_provenance_i32(ptr addrspace(1) %p0) {
ret ptr addrspace(1) %r
}
+define ptr @ptrmask_is_nop0(ptr align 8 %p) {
+; CHECK-LABEL: define ptr @ptrmask_is_nop0
+; CHECK-SAME: (ptr align 8 [[P:%.*]]) {
+; CHECK-NEXT: ret ptr [[P]]
+;
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %p, i64 -8)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_is_nop1(ptr align 8 %p) {
+; CHECK-LABEL: define ptr @ptrmask_is_nop1
+; CHECK-SAME: (ptr align 8 [[P:%.*]]) {
+; CHECK-NEXT: ret ptr [[P]]
+;
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %p, i64 -4)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep0(ptr align 8 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep0
+; CHECK-SAME: (ptr align 8 [[P:%.*]]) {
+; CHECK-NEXT: [[PM:%.*]] = call align 16 ptr @llvm.ptrmask.p0.i64(ptr [[P]], i64 -16)
+; CHECK-NEXT: ret ptr [[PM]]
+;
+ %gep = getelementptr i8, ptr %p, i32 5
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -16)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep1(ptr align 8 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep1
+; CHECK-SAME: (ptr align 8 [[P:%.*]]) {
+; CHECK-NEXT: ret ptr [[P]]
+;
+ %gep = getelementptr i8, ptr %p, i32 6
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -8)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep2(ptr align 16 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep2
+; CHECK-SAME: (ptr align 16 [[P:%.*]]) {
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr i8, ptr [[P]], i64 12
+; CHECK-NEXT: ret ptr [[GEP1]]
+;
+ %gep = getelementptr i8, ptr %p, i32 15
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -4)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep4(ptr align 8 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep4
+; CHECK-SAME: (ptr align 8 [[P:%.*]]) {
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr i8, ptr [[P]], i64 24
+; CHECK-NEXT: [[PM:%.*]] = call align 16 ptr @llvm.ptrmask.p0.i64(ptr [[GEP1]], i64 -16)
+; CHECK-NEXT: ret ptr [[PM]]
+;
+ %gep = getelementptr i8, ptr %p, i32 29
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -16)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep5(ptr align 8 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep5
+; CHECK-SAME: (ptr align 8 [[P:%.*]]) {
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr i8, ptr [[P]], i64 24
+; CHECK-NEXT: ret ptr [[GEP1]]
+;
+ %gep = getelementptr i8, ptr %p, i32 30
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -8)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep6(ptr align 16 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep6
+; CHECK-SAME: (ptr align 16 [[P:%.*]]) {
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr i8, ptr [[P]], i64 28
+; CHECK-NEXT: ret ptr [[GEP1]]
+;
+ %gep = getelementptr i8, ptr %p, i32 31
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -4)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep_indirect0(ptr align 16 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep_indirect0
+; CHECK-SAME: (ptr align 16 [[P:%.*]]) {
+; 44 from 4*sizeof(i32) + (31 & -4)
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr i8, ptr [[P]], i64 44
+; CHECK-NEXT: ret ptr [[GEP1]]
+;
+ %gep0 = getelementptr i32, ptr %p, i32 4
+ %gep1 = getelementptr i8, ptr %gep0, i32 31
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep1, i64 -4)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_modified_gep_indirect1(ptr %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep_indirect1
+; CHECK-SAME: (ptr [[P:%.*]]) {
+
+; CHECK-NEXT: [[R:%.*]] = call align 16 ptr @llvm.ptrmask.p0.i64(ptr [[P]], i64 -16)
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr i8, ptr [[R]], i64 32
+; CHECK-NEXT: ret ptr [[GEP]]
+;
+ %pm0 = call ptr @llvm.ptrmask.p0.i64(ptr %p, i64 -16)
+ %pgep = getelementptr i8, ptr %pm0, i64 33
+ %r = call ptr @llvm.ptrmask.p0.i64(ptr %pgep, i64 -16)
+ ret ptr %r
+}
+
+define ptr @ptrmask_to_modified_gep_zero_argument() {
+; CHECK-LABEL: define ptr @ptrmask_to_modified_gep_zero_argument() {
+; CHECK-NEXT: [[P:%.*]] = call nonnull align 4 ptr @llvm.ptrmask.p0.i64(ptr nonnull inttoptr (i64 31 to ptr), i64 28)
+; CHECK-NEXT: ret ptr [[P]]
+;
+ %gep = getelementptr inbounds i8, ptr null, i32 31
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -4)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_to_preserves_inbounds(ptr align 16 %p) {
+; CHECK-LABEL: define ptr @ptrmask_to_preserves_inbounds
+; CHECK-SAME: (ptr align 16 [[P:%.*]]) {
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr inbounds i8, ptr [[P]], i64 28
+; CHECK-NEXT: ret ptr [[GEP1]]
+;
+ %gep = getelementptr inbounds i8, ptr %p, i32 31
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -4)
+ ret ptr %pm
+}
+
+define ptr @ptrmask_of_gep_requires_i8(ptr align 8 %p) {
+; CHECK-LABEL: define ptr @ptrmask_of_gep_requires_i8
+; CHECK-SAME: (ptr align 8 [[P:%.*]]) {
+; CHECK-NEXT: [[GEP1:%.*]] = getelementptr i8, ptr [[P]], i64 8
+; CHECK-NEXT: [[PM:%.*]] = call align 16 ptr @llvm.ptrmask.p0.i64(ptr [[GEP1]], i64 -16)
+; CHECK-NEXT: ret ptr [[PM]]
+;
+ %gep = getelementptr i16, ptr %p, i32 5
+ %pm = call ptr @llvm.ptrmask.p0.i64(ptr %gep, i64 -16)
+ ret ptr %pm
+}
+
+define <2 x ptr> @ptrmask_of_gep_vector_type_unimplemented(<2 x ptr> align 8 %p) {
+; CHECK-LABEL: define <2 x ptr> @ptrmask_of_gep_vector_type_unimplemented
+; CHECK-SAME: (<2 x ptr> align 8 [[P:%.*]]) {
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr i8, <2 x ptr> [[P]], i64 17
+; CHECK-NEXT: [[PM:%.*]] = call align 32 <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr> [[GEP]], <2 x i64> <i64 -96, i64 -96>)
+; CHECK-NEXT: ret <2 x ptr> [[PM]]
+;
+ %gep = getelementptr i8, <2 x ptr> %p, i32 17
+ %pm = call <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr> %gep, <2 x i64> <i64 -96, i64 -96>)
+ ret <2 x ptr> %pm
+}
+
define ptr @ptrmask_is_useless0(i64 %i, i64 %m) {
; CHECK-LABEL: define ptr @ptrmask_is_useless0
; CHECK-SAME: (i64 [[I:%.*]], i64 [[M:%.*]]) {
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