[llvm] 6922ab7 - Revert "[InstCombine] Extract bitcast -> gep transform"
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Mon Jun 21 12:34:29 PDT 2021
Author: Nikita Popov
Date: 2021-06-21T21:34:17+02:00
New Revision: 6922ab73a5a5b0d6a65f0b8796e5fae4345dbbd9
URL: https://github.com/llvm/llvm-project/commit/6922ab73a5a5b0d6a65f0b8796e5fae4345dbbd9
DIFF: https://github.com/llvm/llvm-project/commit/6922ab73a5a5b0d6a65f0b8796e5fae4345dbbd9.diff
LOG: Revert "[InstCombine] Extract bitcast -> gep transform"
This reverts commit d9f5d7b959de36085944d4a99a73f3053f953796.
This reverts commit 5780611d7e044ef56c4214df2c236ef5e15545ab.
This causes a failure in Coroutine tests.
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
Removed:
llvm/test/Transforms/InstCombine/opaque-ptr.ll
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index 24187d50a484..9b38eb6ab24d 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -2603,57 +2603,6 @@ Instruction *InstCombinerImpl::optimizeBitCastFromPhi(CastInst &CI,
return RetVal;
}
-static Instruction *convertBitCastToGEP(BitCastInst &CI, IRBuilderBase &Builder,
- const DataLayout &DL) {
- Value *Src = CI.getOperand(0);
- PointerType *SrcPTy = cast<PointerType>(Src->getType());
- PointerType *DstPTy = cast<PointerType>(CI.getType());
-
- // Bitcasts involving opaque pointers cannot be converted into a GEP.
- if (SrcPTy->isOpaque() || DstPTy->isOpaque())
- return nullptr;
-
- Type *DstElTy = DstPTy->getElementType();
- Type *SrcElTy = SrcPTy->getElementType();
-
- // When the type pointed to is not sized the cast cannot be
- // turned into a gep.
- if (!SrcElTy->isSized())
- return nullptr;
-
- // If the source and destination are pointers, and this cast is equivalent
- // to a getelementptr X, 0, 0, 0... turn it into the appropriate gep.
- // This can enhance SROA and other transforms that want type-safe pointers.
- unsigned NumZeros = 0;
- while (SrcElTy && SrcElTy != DstElTy) {
- SrcElTy = GetElementPtrInst::getTypeAtIndex(SrcElTy, (uint64_t)0);
- ++NumZeros;
- }
-
- // If we found a path from the src to dest, create the getelementptr now.
- if (SrcElTy == DstElTy) {
- SmallVector<Value *, 8> Idxs(NumZeros + 1, Builder.getInt32(0));
- GetElementPtrInst *GEP =
- GetElementPtrInst::Create(SrcPTy->getElementType(), Src, Idxs);
-
- // If the source pointer is dereferenceable, then assume it points to an
- // allocated object and apply "inbounds" to the GEP.
- bool CanBeNull, CanBeFreed;
- if (Src->getPointerDereferenceableBytes(DL, CanBeNull, CanBeFreed)) {
- // In a non-default address space (not 0), a null pointer can not be
- // assumed inbounds, so ignore that case (dereferenceable_or_null).
- // The reason is that 'null' is not treated
diff erently in these address
- // spaces, and we consequently ignore the 'gep inbounds' special case
- // for 'null' which allows 'inbounds' on 'null' if the indices are
- // zeros.
- if (SrcPTy->getAddressSpace() == 0 || !CanBeNull)
- GEP->setIsInBounds();
- }
- return GEP;
- }
- return nullptr;
-}
-
Instruction *InstCombinerImpl::visitBitCast(BitCastInst &CI) {
// If the operands are integer typed then apply the integer transforms,
// otherwise just apply the common ones.
@@ -2667,6 +2616,11 @@ Instruction *InstCombinerImpl::visitBitCast(BitCastInst &CI) {
return replaceInstUsesWith(CI, Src);
if (isa<PointerType>(SrcTy) && isa<PointerType>(DestTy)) {
+ PointerType *SrcPTy = cast<PointerType>(SrcTy);
+ PointerType *DstPTy = cast<PointerType>(DestTy);
+ Type *DstElTy = DstPTy->getElementType();
+ Type *SrcElTy = SrcPTy->getElementType();
+
// If we are casting a alloca to a pointer to a type of the same
// size, rewrite the allocation instruction to allocate the "right" type.
// There is no need to modify malloc calls because it is their bitcast that
@@ -2675,8 +2629,43 @@ Instruction *InstCombinerImpl::visitBitCast(BitCastInst &CI) {
if (Instruction *V = PromoteCastOfAllocation(CI, *AI))
return V;
- if (Instruction *I = convertBitCastToGEP(CI, Builder, DL))
- return I;
+ // When the type pointed to is not sized the cast cannot be
+ // turned into a gep.
+ Type *PointeeType =
+ cast<PointerType>(Src->getType()->getScalarType())->getElementType();
+ if (!PointeeType->isSized())
+ return nullptr;
+
+ // If the source and destination are pointers, and this cast is equivalent
+ // to a getelementptr X, 0, 0, 0... turn it into the appropriate gep.
+ // This can enhance SROA and other transforms that want type-safe pointers.
+ unsigned NumZeros = 0;
+ while (SrcElTy && SrcElTy != DstElTy) {
+ SrcElTy = GetElementPtrInst::getTypeAtIndex(SrcElTy, (uint64_t)0);
+ ++NumZeros;
+ }
+
+ // If we found a path from the src to dest, create the getelementptr now.
+ if (SrcElTy == DstElTy) {
+ SmallVector<Value *, 8> Idxs(NumZeros + 1, Builder.getInt32(0));
+ GetElementPtrInst *GEP =
+ GetElementPtrInst::Create(SrcPTy->getElementType(), Src, Idxs);
+
+ // If the source pointer is dereferenceable, then assume it points to an
+ // allocated object and apply "inbounds" to the GEP.
+ bool CanBeNull, CanBeFreed;
+ if (Src->getPointerDereferenceableBytes(DL, CanBeNull, CanBeFreed)) {
+ // In a non-default address space (not 0), a null pointer can not be
+ // assumed inbounds, so ignore that case (dereferenceable_or_null).
+ // The reason is that 'null' is not treated
diff erently in these address
+ // spaces, and we consequently ignore the 'gep inbounds' special case
+ // for 'null' which allows 'inbounds' on 'null' if the indices are
+ // zeros.
+ if (SrcPTy->getAddressSpace() == 0 || !CanBeNull)
+ GEP->setIsInBounds();
+ }
+ return GEP;
+ }
}
if (FixedVectorType *DestVTy = dyn_cast<FixedVectorType>(DestTy)) {
diff --git a/llvm/test/Transforms/InstCombine/opaque-ptr.ll b/llvm/test/Transforms/InstCombine/opaque-ptr.ll
deleted file mode 100644
index 1bf205ca9141..000000000000
--- a/llvm/test/Transforms/InstCombine/opaque-ptr.ll
+++ /dev/null
@@ -1,43 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
-; RUN: opt -S -instcombine < %s | FileCheck %s
-
-define ptr @bitcast_opaque_to_opaque(ptr %a) {
-; CHECK-LABEL: @bitcast_opaque_to_opaque(
-; CHECK-NEXT: ret ptr [[A:%.*]]
-;
- %b = bitcast ptr %a to ptr
- ret ptr %b
-}
-
-define ptr @bitcast_typed_to_opaque(i8* %a) {
-; CHECK-LABEL: @bitcast_typed_to_opaque(
-; CHECK-NEXT: [[B:%.*]] = bitcast i8* [[A:%.*]] to ptr
-; CHECK-NEXT: ret ptr [[B]]
-;
- %b = bitcast i8* %a to ptr
- ret ptr %b
-}
-
-define i8* @bitcast_opaque_to_typed(ptr %a) {
-; CHECK-LABEL: @bitcast_opaque_to_typed(
-; CHECK-NEXT: [[B:%.*]] = bitcast ptr [[A:%.*]] to i8*
-; CHECK-NEXT: ret i8* [[B]]
-;
- %b = bitcast ptr %a to i8*
- ret i8* %b
-}
-
-;define ptr @addrspacecast_opaque_to_opaque(ptr addrspace(1) %a) {
-; %b = addrspacecast ptr addrspace(1) %a to ptr
-; ret ptr %b
-;}
-
-;define ptr @addrspacecast_typed_to_opaque(i8 addrspace(1)* %a) {
-; %b = addrspacecast i8 addrspace(1)* %a to ptr
-; ret ptr %b
-;}
-
-;define i8* @addrspacecast_opaque_to_typed(ptr addrspace(1) %a) {
-; %b = addrspacecast ptr addrspace(1) %a to i8*
-; ret i8* %b
-;}
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