[llvm-commits] [llvm] r165870 - in /llvm/trunk: lib/Transforms/Scalar/SROA.cpp test/Transforms/SROA/alignment.ll test/Transforms/SROA/basictest.ll
Chandler Carruth
chandlerc at gmail.com
Sat Oct 13 03:49:33 PDT 2012
Author: chandlerc
Date: Sat Oct 13 05:49:33 2012
New Revision: 165870
URL: http://llvm.org/viewvc/llvm-project?rev=165870&view=rev
Log:
Teach SROA to cope with wrapper aggregates. These show up a lot in ABI
type coercion code, especially when targetting ARM. Things like [1
x i32] instead of i32 are very common there.
The goal of this logic is to ensure that when we are picking an alloca
type, we look through such wrapper aggregates and across any zero-length
aggregate elements to find the simplest type possible to form a type
partition.
This logic should (generally speaking) rarely fire. It only ends up
kicking in when an alloca is accessed using two different types (for
instance, i32 and float), and the underlying alloca type has wrapper
aggregates around it. I noticed a significant amount of this occurring
looking at stepanov_abstraction generated code for arm, and suspect it
happens elsewhere as well.
Note that this doesn't yet address truly heinous IR productions such as
PR14059 is concerning. Those result in mismatched *sizes* of types in
addition to mismatched access and alloca types.
Modified:
llvm/trunk/lib/Transforms/Scalar/SROA.cpp
llvm/trunk/test/Transforms/SROA/alignment.ll
llvm/trunk/test/Transforms/SROA/basictest.ll
Modified: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SROA.cpp?rev=165870&r1=165869&r2=165870&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SROA.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp Sat Oct 13 05:49:33 2012
@@ -3049,6 +3049,36 @@
};
}
+/// \brief Strip aggregate type wrapping.
+///
+/// This removes no-op aggregate types wrapping an underlying type. It will
+/// strip as many layers of types as it can without changing either the type
+/// size or the allocated size.
+static Type *stripAggregateTypeWrapping(const DataLayout &DL, Type *Ty) {
+ if (Ty->isSingleValueType())
+ return Ty;
+
+ uint64_t AllocSize = DL.getTypeAllocSize(Ty);
+ uint64_t TypeSize = DL.getTypeSizeInBits(Ty);
+
+ Type *InnerTy;
+ if (ArrayType *ArrTy = dyn_cast<ArrayType>(Ty)) {
+ InnerTy = ArrTy->getElementType();
+ } else if (StructType *STy = dyn_cast<StructType>(Ty)) {
+ const StructLayout *SL = DL.getStructLayout(STy);
+ unsigned Index = SL->getElementContainingOffset(0);
+ InnerTy = STy->getElementType(Index);
+ } else {
+ return Ty;
+ }
+
+ if (AllocSize > DL.getTypeAllocSize(InnerTy) ||
+ TypeSize > DL.getTypeSizeInBits(InnerTy))
+ return Ty;
+
+ return stripAggregateTypeWrapping(DL, InnerTy);
+}
+
/// \brief Try to find a partition of the aggregate type passed in for a given
/// offset and size.
///
@@ -3065,7 +3095,7 @@
static Type *getTypePartition(const DataLayout &TD, Type *Ty,
uint64_t Offset, uint64_t Size) {
if (Offset == 0 && TD.getTypeAllocSize(Ty) == Size)
- return Ty;
+ return stripAggregateTypeWrapping(TD, Ty);
if (SequentialType *SeqTy = dyn_cast<SequentialType>(Ty)) {
// We can't partition pointers...
@@ -3094,7 +3124,7 @@
assert(Offset == 0);
if (Size == ElementSize)
- return ElementTy;
+ return stripAggregateTypeWrapping(TD, ElementTy);
assert(Size > ElementSize);
uint64_t NumElements = Size / ElementSize;
if (NumElements * ElementSize != Size)
@@ -3130,7 +3160,7 @@
assert(Offset == 0);
if (Size == ElementSize)
- return ElementTy;
+ return stripAggregateTypeWrapping(TD, ElementTy);
StructType::element_iterator EI = STy->element_begin() + Index,
EE = STy->element_end();
Modified: llvm/trunk/test/Transforms/SROA/alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SROA/alignment.ll?rev=165870&r1=165869&r2=165870&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SROA/alignment.ll (original)
+++ llvm/trunk/test/Transforms/SROA/alignment.ll Sat Oct 13 05:49:33 2012
@@ -84,37 +84,6 @@
ret void
}
-%struct.S = type { i8, { i64 } }
-
-define void @test4() {
-; This test case triggered very strange alignment behavior with memcpy due to
-; strange splitting. Reported by Duncan.
-; CHECK: @test4
-
-entry:
- %D.2113 = alloca %struct.S
- %Op = alloca %struct.S
- %D.2114 = alloca %struct.S
- %gep1 = getelementptr inbounds %struct.S* %Op, i32 0, i32 0
- store i8 0, i8* %gep1, align 8
- %gep2 = getelementptr inbounds %struct.S* %Op, i32 0, i32 1, i32 0
- %cast = bitcast i64* %gep2 to double*
- store double 0.000000e+00, double* %cast, align 8
- store i64 0, i64* %gep2, align 8
- %dst1 = bitcast %struct.S* %D.2114 to i8*
- %src1 = bitcast %struct.S* %Op to i8*
- call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst1, i8* %src1, i32 16, i32 8, i1 false)
- %dst2 = bitcast %struct.S* %D.2113 to i8*
- %src2 = bitcast %struct.S* %D.2114 to i8*
- call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst2, i8* %src2, i32 16, i32 8, i1 false)
-; We get 3 memcpy calls with various reasons to shrink their alignment to 1.
-; CHECK: @llvm.memcpy.p0i8.p0i8.i32(i8* %{{.*}}, i8* %{{.*}}, i32 3, i32 1, i1 false)
-; CHECK: @llvm.memcpy.p0i8.p0i8.i32(i8* %{{.*}}, i8* %{{.*}}, i32 8, i32 1, i1 false)
-; CHECK: @llvm.memcpy.p0i8.p0i8.i32(i8* %{{.*}}, i8* %{{.*}}, i32 11, i32 1, i1 false)
-
- ret void
-}
-
define void @test5() {
; Test that we preserve underaligned loads and stores when splitting.
; CHECK: @test5
Modified: llvm/trunk/test/Transforms/SROA/basictest.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SROA/basictest.ll?rev=165870&r1=165869&r2=165870&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SROA/basictest.ll (original)
+++ llvm/trunk/test/Transforms/SROA/basictest.ll Sat Oct 13 05:49:33 2012
@@ -968,3 +968,47 @@
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %cast0, i8* %cast1, i32 12, i32 0, i1 false)
ret void
}
+
+define i32 @test22(i32 %x) {
+; Test that SROA and promotion is not confused by a grab bax mixture of pointer
+; types involving wrapper aggregates and zero-length aggregate members.
+; CHECK: @test22
+
+entry:
+ %a1 = alloca { { [1 x { i32 }] } }
+ %a2 = alloca { {}, { float }, [0 x i8] }
+ %a3 = alloca { [0 x i8], { [0 x double], [1 x [1 x <4 x i8>]], {} }, { { {} } } }
+; CHECK-NOT: alloca
+
+ %wrap1 = insertvalue [1 x { i32 }] undef, i32 %x, 0, 0
+ %gep1 = getelementptr { { [1 x { i32 }] } }* %a1, i32 0, i32 0, i32 0
+ store [1 x { i32 }] %wrap1, [1 x { i32 }]* %gep1
+
+ %gep2 = getelementptr { { [1 x { i32 }] } }* %a1, i32 0, i32 0
+ %ptrcast1 = bitcast { [1 x { i32 }] }* %gep2 to { [1 x { float }] }*
+ %load1 = load { [1 x { float }] }* %ptrcast1
+ %unwrap1 = extractvalue { [1 x { float }] } %load1, 0, 0
+
+ %wrap2 = insertvalue { {}, { float }, [0 x i8] } undef, { float } %unwrap1, 1
+ store { {}, { float }, [0 x i8] } %wrap2, { {}, { float }, [0 x i8] }* %a2
+
+ %gep3 = getelementptr { {}, { float }, [0 x i8] }* %a2, i32 0, i32 1, i32 0
+ %ptrcast2 = bitcast float* %gep3 to <4 x i8>*
+ %load3 = load <4 x i8>* %ptrcast2
+ %valcast1 = bitcast <4 x i8> %load3 to i32
+
+ %wrap3 = insertvalue [1 x [1 x i32]] undef, i32 %valcast1, 0, 0
+ %wrap4 = insertvalue { [1 x [1 x i32]], {} } undef, [1 x [1 x i32]] %wrap3, 0
+ %gep4 = getelementptr { [0 x i8], { [0 x double], [1 x [1 x <4 x i8>]], {} }, { { {} } } }* %a3, i32 0, i32 1
+ %ptrcast3 = bitcast { [0 x double], [1 x [1 x <4 x i8>]], {} }* %gep4 to { [1 x [1 x i32]], {} }*
+ store { [1 x [1 x i32]], {} } %wrap4, { [1 x [1 x i32]], {} }* %ptrcast3
+
+ %gep5 = getelementptr { [0 x i8], { [0 x double], [1 x [1 x <4 x i8>]], {} }, { { {} } } }* %a3, i32 0, i32 1, i32 1, i32 0
+ %ptrcast4 = bitcast [1 x <4 x i8>]* %gep5 to { {}, float, {} }*
+ %load4 = load { {}, float, {} }* %ptrcast4
+ %unwrap2 = extractvalue { {}, float, {} } %load4, 1
+ %valcast2 = bitcast float %unwrap2 to i32
+
+ ret i32 %valcast2
+; CHECK: ret i32
+}
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