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Disable the optimization about promoting vector-element-access with symbolic index.
This optimization is unstable at this moment; it
1) block us on a very important application
2) PR15200
3) test6 and test7 in test/Transforms/ScalarRepl/dynamic-vector-gep.ll
(the CHECK command compare the output against wrong result)
I personally believe this optimization should not have any impact on the
autovectorized code, as auto-vectorizer is supposed to put gather/scatter
in a "right" way. Although in theory downstream optimizaters might reveal
some gather/scatter optimization opportunities, the chance is quite slim.
For the hand-crafted vectorizing code, in term of redundancy elimination,
load-CSE, copy-propagation and DSE can collectively achieve the same result,
but in much simpler way. On the other hand, these optimizers are able to
improve the code in a incremental way; in contrast, SROA is sort of all-or-none
approach. However, SROA might slighly win in stack size, as it tries to figure
out a stretch of memory tightenly cover the area accessed by the dynamic index.
rdar://13174884
PR15200
llvm-svn: 178912
This commit is contained in:
Shuxin Yang
parent
70bcdf07be
commit
5cf388a00f
@ -1724,17 +1724,8 @@ void SROA::isSafeGEP(GetElementPtrInst *GEPI,
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continue;
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ConstantInt *IdxVal = dyn_cast<ConstantInt>(GEPIt.getOperand());
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if (!IdxVal) {
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// Non constant GEPs are only a problem on arrays, structs, and pointers
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// Vectors can be dynamically indexed.
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// FIXME: Add support for dynamic indexing on arrays. This should be
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// ok on any subarrays of the alloca array, eg, a[0][i] is ok, but a[i][0]
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// isn't.
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if (!(*GEPIt)->isVectorTy())
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return MarkUnsafe(Info, GEPI);
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NonConstant = true;
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NonConstantIdxSize = TD->getTypeAllocSize(*GEPIt);
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}
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if (!IdxVal)
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return MarkUnsafe(Info, GEPI);
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}
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// Compute the offset due to this GEP and check if the alloca has a
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@ -1,167 +0,0 @@
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; RUN: opt < %s -scalarrepl -S | FileCheck %s
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target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64"
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target triple = "x86_64-apple-darwin10.0.0"
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; CHECK: @test1
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; CHECK: %[[alloc:[\.a-z0-9]*]] = alloca <4 x float>
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; CHECK: store <4 x float> zeroinitializer, <4 x float>* %[[alloc]]
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; CHECK: memset
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; CHECK: extractelement <4 x float> zeroinitializer, i32 %idx2
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; Split the array but don't replace the memset with an insert
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; element as its not a constant offset.
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; The load, however, can be replaced with an extract element.
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define float @test1(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca [4 x <4 x float>]
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store [4 x <4 x float>] zeroinitializer, [4 x <4 x float>]* %0
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%ptr1 = getelementptr [4 x <4 x float>]* %0, i32 0, i32 0, i32 %idx1
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%cast = bitcast float* %ptr1 to i8*
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call void @llvm.memset.p0i8.i32(i8* %cast, i8 0, i32 4, i32 4, i1 false)
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%ptr2 = getelementptr [4 x <4 x float>]* %0, i32 0, i32 1, i32 %idx2
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%ret = load float* %ptr2
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ret float %ret
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}
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; CHECK: @test2
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; CHECK: %[[ins:[\.a-z0-9]*]] = insertelement <4 x float> zeroinitializer, float 1.000000e+00, i32 %idx1
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; CHECK: extractelement <4 x float> %[[ins]], i32 %idx2
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; Do SROA on the array when it has dynamic vector reads and writes.
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define float @test2(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca [4 x <4 x float>]
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store [4 x <4 x float>] zeroinitializer, [4 x <4 x float>]* %0
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%ptr1 = getelementptr [4 x <4 x float>]* %0, i32 0, i32 0, i32 %idx1
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store float 1.0, float* %ptr1
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%ptr2 = getelementptr [4 x <4 x float>]* %0, i32 0, i32 0, i32 %idx2
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%ret = load float* %ptr2
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ret float %ret
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}
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; CHECK: test3
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; CHECK: %0 = alloca [4 x <4 x float>]
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; CHECK-NOT: alloca
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; Don't do SROA on a dynamically indexed vector when it spans
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; more than one array element of the alloca array it is within.
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define float @test3(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca [4 x <4 x float>]
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store [4 x <4 x float>] zeroinitializer, [4 x <4 x float>]* %0
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%bigvec = bitcast [4 x <4 x float>]* %0 to <16 x float>*
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%ptr1 = getelementptr <16 x float>* %bigvec, i32 0, i32 %idx1
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store float 1.0, float* %ptr1
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%ptr2 = getelementptr <16 x float>* %bigvec, i32 0, i32 %idx2
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%ret = load float* %ptr2
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ret float %ret
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}
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; CHECK: test4
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; CHECK: insertelement <16 x float> zeroinitializer, float 1.000000e+00, i32 %idx1
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; CHECK: extractelement <16 x float> %0, i32 %idx2
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; Don't do SROA on a dynamically indexed vector when it spans
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; more than one array element of the alloca array it is within.
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; However, unlike test3, the store is on the vector type
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; so SROA will convert the large alloca into the large vector
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; type and do all accesses with insert/extract element
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define float @test4(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca [4 x <4 x float>]
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%bigvec = bitcast [4 x <4 x float>]* %0 to <16 x float>*
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store <16 x float> zeroinitializer, <16 x float>* %bigvec
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%ptr1 = getelementptr <16 x float>* %bigvec, i32 0, i32 %idx1
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store float 1.0, float* %ptr1
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%ptr2 = getelementptr <16 x float>* %bigvec, i32 0, i32 %idx2
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%ret = load float* %ptr2
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ret float %ret
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}
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; CHECK: @test5
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; CHECK: %0 = alloca [4 x <4 x float>]
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; CHECK-NOT: alloca
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; Don't do SROA as the is a second dynamically indexed array
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; which may span multiple elements of the alloca.
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define float @test5(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca [4 x <4 x float>]
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store [4 x <4 x float>] zeroinitializer, [4 x <4 x float>]* %0
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%ptr1 = getelementptr [4 x <4 x float>]* %0, i32 0, i32 0, i32 %idx1
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%ptr2 = bitcast float* %ptr1 to [1 x <2 x float>]*
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%ptr3 = getelementptr [1 x <2 x float>]* %ptr2, i32 0, i32 0, i32 %idx1
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store float 1.0, float* %ptr1
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%ptr4 = getelementptr [4 x <4 x float>]* %0, i32 0, i32 0, i32 %idx2
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%ret = load float* %ptr4
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ret float %ret
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}
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; CHECK: test6
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; CHECK: insertelement <4 x float> zeroinitializer, float 1.000000e+00, i32 %idx1
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; CHECK: extractelement <4 x float> zeroinitializer, i32 %idx2
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%vector.pair = type { %vector.anon, %vector.anon }
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%vector.anon = type { %vector }
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%vector = type { <4 x float> }
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; Dynamic GEPs on vectors were crashing when the vector was inside a struct
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; as the new GEP for the new alloca might not include all the indices from
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; the original GEP, just the indices it needs to get to the correct offset of
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; some type, not necessarily the dynamic vector.
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; This test makes sure we don't have this crash.
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define float @test6(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca %vector.pair
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store %vector.pair zeroinitializer, %vector.pair* %0
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%ptr1 = getelementptr %vector.pair* %0, i32 0, i32 0, i32 0, i32 0, i32 %idx1
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store float 1.0, float* %ptr1
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%ptr2 = getelementptr %vector.pair* %0, i32 0, i32 1, i32 0, i32 0, i32 %idx2
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%ret = load float* %ptr2
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ret float %ret
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}
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; CHECK: test7
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; CHECK: insertelement <4 x float> zeroinitializer, float 1.000000e+00, i32 %idx1
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; CHECK: extractelement <4 x float> zeroinitializer, i32 %idx2
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%array.pair = type { [2 x %array.anon], %array.anon }
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%array.anon = type { [2 x %vector] }
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; This is the same as test6 and tests the same crash, but on arrays.
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define float @test7(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca %array.pair
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store %array.pair zeroinitializer, %array.pair* %0
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%ptr1 = getelementptr %array.pair* %0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 %idx1
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store float 1.0, float* %ptr1
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%ptr2 = getelementptr %array.pair* %0, i32 0, i32 1, i32 0, i32 0, i32 0, i32 %idx2
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%ret = load float* %ptr2
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ret float %ret
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}
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; CHECK: test8
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; CHECK: %[[offset1:[\.a-z0-9]*]] = add i32 %idx1, 1
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; CHECK: %[[ins:[\.a-z0-9]*]] = insertelement <4 x float> zeroinitializer, float 1.000000e+00, i32 %[[offset1]]
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; CHECK: %[[offset2:[\.a-z0-9]*]] = add i32 %idx2, 2
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; CHECK: extractelement <4 x float> %[[ins]], i32 %[[offset2]]
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; Do SROA on the vector when it has dynamic vector reads and writes
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; from a non-zero offset.
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define float @test8(i32 %idx1, i32 %idx2) {
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entry:
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%0 = alloca <4 x float>
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store <4 x float> zeroinitializer, <4 x float>* %0
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%ptr1 = getelementptr <4 x float>* %0, i32 0, i32 1
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%ptr2 = bitcast float* %ptr1 to <3 x float>*
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%ptr3 = getelementptr <3 x float>* %ptr2, i32 0, i32 %idx1
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store float 1.0, float* %ptr3
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%ptr4 = getelementptr <4 x float>* %0, i32 0, i32 2
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%ptr5 = bitcast float* %ptr4 to <2 x float>*
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%ptr6 = getelementptr <2 x float>* %ptr5, i32 0, i32 %idx2
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%ret = load float* %ptr6
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ret float %ret
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}
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declare void @llvm.memset.p0i8.i32(i8*, i8, i32, i32, i1)
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