r372225 - Revert r372082 "[Clang] Pragma vectorize_width() implies vectorize(enable)"
Hans Wennborg via cfe-commits
cfe-commits at lists.llvm.org
Wed Sep 18 06:41:51 PDT 2019
Author: hans
Date: Wed Sep 18 06:41:51 2019
New Revision: 372225
URL: http://llvm.org/viewvc/llvm-project?rev=372225&view=rev
Log:
Revert r372082 "[Clang] Pragma vectorize_width() implies vectorize(enable)"
This broke the Chromium build. Consider the following code:
float ScaleSumSamples_C(const float* src, float* dst, float scale, int width) {
float fsum = 0.f;
int i;
#if defined(__clang__)
#pragma clang loop vectorize_width(4)
#endif
for (i = 0; i < width; ++i) {
float v = *src++;
fsum += v * v;
*dst++ = v * scale;
}
return fsum;
}
Compiling at -Oz, Clang now warns:
$ clang++ -target x86_64 -Oz -c /tmp/a.cc
/tmp/a.cc:1:7: warning: loop not vectorized: the optimizer was unable to
perform the requested transformation; the transformation might be disabled or
specified as part of an unsupported transformation ordering
[-Wpass-failed=transform-warning]
this suggests it's not actually enabling vectorization hard enough.
At -Os it asserts instead:
$ build.release/bin/clang++ -target x86_64 -Os -c /tmp/a.cc
clang-10: /work/llvm.monorepo/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:2734: void
llvm::InnerLoopVectorizer::emitMemRuntimeChecks(llvm::Loop*, llvm::BasicBlock*): Assertion `
!BB->getParent()->hasOptSize() && "Cannot emit memory checks when optimizing for size"' failed.
Of course neither of these are what the developer expected from the pragma.
> Specifying the vectorization width was supposed to implicitly enable
> vectorization, except that it wasn't really doing this. It was only
> setting the vectorize.width metadata, but not vectorize.enable.
>
> This should fix PR27643.
>
> Differential Revision: https://reviews.llvm.org/D66290
Modified:
cfe/trunk/lib/CodeGen/CGLoopInfo.cpp
cfe/trunk/test/CodeGenCXX/pragma-loop-predicate.cpp
cfe/trunk/test/CodeGenCXX/pragma-loop.cpp
Modified: cfe/trunk/lib/CodeGen/CGLoopInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGLoopInfo.cpp?rev=372225&r1=372224&r2=372225&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGLoopInfo.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGLoopInfo.cpp Wed Sep 18 06:41:51 2019
@@ -270,14 +270,6 @@ LoopInfo::createLoopVectorizeMetadata(co
// Setting vectorize.width
if (Attrs.VectorizeWidth > 0) {
- // This implies vectorize.enable = true, but only add it when it is not
- // already enabled.
- if (Attrs.VectorizeEnable != LoopAttributes::Enable)
- Args.push_back(
- MDNode::get(Ctx, {MDString::get(Ctx, "llvm.loop.vectorize.enable"),
- ConstantAsMetadata::get(ConstantInt::get(
- llvm::Type::getInt1Ty(Ctx), 1))}));
-
Metadata *Vals[] = {
MDString::get(Ctx, "llvm.loop.vectorize.width"),
ConstantAsMetadata::get(ConstantInt::get(llvm::Type::getInt32Ty(Ctx),
Modified: cfe/trunk/test/CodeGenCXX/pragma-loop-predicate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/pragma-loop-predicate.cpp?rev=372225&r1=372224&r2=372225&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/pragma-loop-predicate.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/pragma-loop-predicate.cpp Wed Sep 18 06:41:51 2019
@@ -58,6 +58,7 @@ void test5(int *List, int Length) {
List[i] = i * 2;
}
+
// CHECK: ![[LOOP0]] = distinct !{![[LOOP0]], !3}
// CHECK-NEXT: !3 = !{!"llvm.loop.vectorize.enable", i1 true}
@@ -69,7 +70,7 @@ void test5(int *List, int Length) {
// CHECK-NEXT: ![[LOOP3]] = distinct !{![[LOOP3]], !5, !3}
-// CHECK-NEXT: ![[LOOP4]] = distinct !{![[LOOP4]], !3, !10}
+// CHECK-NEXT: ![[LOOP4]] = distinct !{![[LOOP4]], !10}
// CHECK-NEXT: !10 = !{!"llvm.loop.vectorize.width", i32 1}
-// CHECK-NEXT: ![[LOOP5]] = distinct !{![[LOOP5]], !3, !10}
+// CHECK-NEXT: ![[LOOP5]] = distinct !{![[LOOP5]], !10}
Modified: cfe/trunk/test/CodeGenCXX/pragma-loop.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/pragma-loop.cpp?rev=372225&r1=372224&r2=372225&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/pragma-loop.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/pragma-loop.cpp Wed Sep 18 06:41:51 2019
@@ -158,41 +158,23 @@ void template_test(double *List, int Len
for_template_constant_expression_test<double, 2, 4, 8>(List, Length);
}
-void vec_width_1(int *List, int Length) {
-// CHECK-LABEL: @{{.*}}vec_width_1{{.*}}(
-// CHECK: br label {{.*}}, !llvm.loop ![[LOOP_15:.*]]
-
- #pragma clang loop vectorize(enable) vectorize_width(1)
- for (int i = 0; i < Length; i++)
- List[i] = i * 2;
-}
-
-void width_1(int *List, int Length) {
-// CHECK-LABEL: @{{.*}}width_1{{.*}}(
-// CHECK: br label {{.*}}, !llvm.loop ![[LOOP_16:.*]]
-
- #pragma clang loop vectorize_width(1)
- for (int i = 0; i < Length; i++)
- List[i] = i * 2;
-}
-
// CHECK: ![[LOOP_1]] = distinct !{![[LOOP_1]], ![[UNROLL_FULL:.*]]}
// CHECK: ![[UNROLL_FULL]] = !{!"llvm.loop.unroll.full"}
-// CHECK: ![[LOOP_2]] = distinct !{![[LOOP_2]], ![[UNROLL_DISABLE:.*]], ![[DISTRIBUTE_DISABLE:.*]], ![[VECTORIZE_ENABLE:.*]], ![[WIDTH_8:.*]], ![[INTERLEAVE_4:.*]]}
+// CHECK: ![[LOOP_2]] = distinct !{![[LOOP_2]], ![[UNROLL_DISABLE:.*]], ![[DISTRIBUTE_DISABLE:.*]], ![[WIDTH_8:.*]], ![[INTERLEAVE_4:.*]]}
// CHECK: ![[UNROLL_DISABLE]] = !{!"llvm.loop.unroll.disable"}
// CHECK: ![[DISTRIBUTE_DISABLE]] = !{!"llvm.loop.distribute.enable", i1 false}
-// CHECK: ![[VECTORIZE_ENABLE]] = !{!"llvm.loop.vectorize.enable", i1 true}
// CHECK: ![[WIDTH_8]] = !{!"llvm.loop.vectorize.width", i32 8}
// CHECK: ![[INTERLEAVE_4]] = !{!"llvm.loop.interleave.count", i32 4}
-// CHECK: ![[LOOP_3]] = distinct !{![[LOOP_3]], ![[INTERLEAVE_4:.*]], ![[VECTORIZE_ENABLE]], ![[FOLLOWUP_VECTOR_3:.*]]}
+// CHECK: ![[LOOP_3]] = distinct !{![[LOOP_3]], ![[INTERLEAVE_4:.*]], ![[INTENABLE_1:.*]], ![[FOLLOWUP_VECTOR_3:.*]]}
+// CHECK: ![[INTENABLE_1]] = !{!"llvm.loop.vectorize.enable", i1 true}
// CHECK: ![[FOLLOWUP_VECTOR_3]] = !{!"llvm.loop.vectorize.followup_all", ![[AFTER_VECTOR_3:.*]]}
// CHECK: ![[AFTER_VECTOR_3]] = distinct !{![[AFTER_VECTOR_3]], ![[ISVECTORIZED:.*]], ![[UNROLL_8:.*]]}
// CHECK: ![[ISVECTORIZED]] = !{!"llvm.loop.isvectorized"}
// CHECK: ![[UNROLL_8]] = !{!"llvm.loop.unroll.count", i32 8}
-// CHECK: ![[LOOP_4]] = distinct !{![[LOOP_4]], ![[VECTORIZE_ENABLE]], ![[WIDTH_2:.*]], ![[INTERLEAVE_2:.*]]}
+// CHECK: ![[LOOP_4]] = distinct !{![[LOOP_4]], ![[WIDTH_2:.*]], ![[INTERLEAVE_2:.*]]}
// CHECK: ![[WIDTH_2]] = !{!"llvm.loop.vectorize.width", i32 2}
// CHECK: ![[INTERLEAVE_2]] = !{!"llvm.loop.interleave.count", i32 2}
@@ -203,7 +185,7 @@ void width_1(int *List, int Length) {
// CHECK: ![[FOLLOWUP_VECTOR_6]] = !{!"llvm.loop.vectorize.followup_all", ![[AFTER_VECTOR_6:.*]]}
// CHECK: ![[AFTER_VECTOR_6]] = distinct !{![[AFTER_VECTOR_6]], ![[ISVECTORIZED:.*]], ![[UNROLL_8:.*]]}
-// CHECK: ![[LOOP_7]] = distinct !{![[LOOP_7]], ![[VECTORIZE_ENABLE]], ![[WIDTH_5:.*]]}
+// CHECK: ![[LOOP_7]] = distinct !{![[LOOP_7]], ![[WIDTH_5:.*]]}
// CHECK: ![[WIDTH_5]] = !{!"llvm.loop.vectorize.width", i32 5}
// CHECK: ![[LOOP_8]] = distinct !{![[LOOP_8]], ![[WIDTH_5:.*]]}
@@ -231,9 +213,5 @@ void width_1(int *List, int Length) {
// CHECK: ![[AFTER_VECTOR_13]] = distinct !{![[AFTER_VECTOR_13]], ![[ISVECTORIZED:.*]], ![[UNROLL_32:.*]]}
// CHECK: ![[UNROLL_32]] = !{!"llvm.loop.unroll.count", i32 32}
-// CHECK: ![[LOOP_14]] = distinct !{![[LOOP_14]], ![[VECTORIZE_ENABLE]], ![[WIDTH_10:.*]]}
+// CHECK: ![[LOOP_14]] = distinct !{![[LOOP_14]], ![[WIDTH_10:.*]]}
// CHECK: ![[WIDTH_10]] = !{!"llvm.loop.vectorize.width", i32 10}
-
-// CHECK: ![[LOOP_15]] = distinct !{![[LOOP_15]], ![[WIDTH_1]], ![[VECTORIZE_ENABLE]]}
-
-// CHECK-NEXT: ![[LOOP_16]] = distinct !{![[LOOP_16]], ![[VECTORIZE_ENABLE]], ![[WIDTH_1]]}
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