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[InstSimplify] Handle vector GEP when simplifying zero indices 

If the base is a scalar and the index is a vector, we can't
simplify, as this is effectively a splat operation.
This commit is contained in:
Nikita Popov 2022-03-11 10:55:48 +01:00
parent d7645f4ef8
commit 02c2106002
2 changed files with 27 additions and 1 deletions
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3
llvm/lib/Analysis/InstructionSimplify.cpp
View File

@ -4499,7 +4499,8 @@ static Value *SimplifyGEPInst(Type *SrcTy, Value *Ptr,
// For opaque pointers an all-zero GEP is a no-op. For typed pointers, // For opaque pointers an all-zero GEP is a no-op. For typed pointers,
// it may be equivalent to a bitcast. // it may be equivalent to a bitcast.
if (Ptr->getType()->isOpaquePointerTy() && if (Ptr->getType()->getScalarType()->isOpaquePointerTy() &&
Ptr->getType() == GEPTy &&
all_of(Indices, [](const auto *V) { return match(V, m_Zero()); })) all_of(Indices, [](const auto *V) { return match(V, m_Zero()); }))
return Ptr; return Ptr;

25
llvm/test/Transforms/InstSimplify/opaque-ptr.ll
View File

@ -26,3 +26,28 @@ define ptr @gep_non_zero_indices2(ptr %p) {
%p2 = getelementptr { i64, i64 }, ptr %p, i64 1, i32 0 %p2 = getelementptr { i64, i64 }, ptr %p, i64 1, i32 0
ret ptr %p2 ret ptr %p2
} }
define <2 x ptr> @scalar_base_vector_index(ptr %p) {
; CHECK-LABEL: @scalar_base_vector_index(
; CHECK-NEXT: [[G:%.*]] = getelementptr { i64, i64 }, ptr [[P:%.*]], <2 x i64> zeroinitializer, i32 0
; CHECK-NEXT: ret <2 x ptr> [[G]]
;
%g = getelementptr { i64, i64 }, ptr %p, <2 x i64> zeroinitializer, i32 0
ret <2 x ptr> %g
}
define <2 x ptr> @vector_base_vector_index(<2 x ptr> %p) {
; CHECK-LABEL: @vector_base_vector_index(
; CHECK-NEXT: ret <2 x ptr> [[P:%.*]]
;
%g = getelementptr { i64, i64 }, <2 x ptr> %p, <2 x i64> zeroinitializer, i32 0
ret <2 x ptr> %g
}
define <2 x ptr> @vector_base_scalar_index(<2 x ptr> %p) {
; CHECK-LABEL: @vector_base_scalar_index(
; CHECK-NEXT: ret <2 x ptr> [[P:%.*]]
;
%g = getelementptr { i64, i64 }, <2 x ptr> %p, i64 0, i32 0
ret <2 x ptr> %g
}