diff options
| -rw-r--r-- | llvm/test/Transforms/LoopVectorize/skip-iterations.ll | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/llvm/test/Transforms/LoopVectorize/skip-iterations.ll b/llvm/test/Transforms/LoopVectorize/skip-iterations.ll index 99160cf4b67..27007aa713b 100644 --- a/llvm/test/Transforms/LoopVectorize/skip-iterations.ll +++ b/llvm/test/Transforms/LoopVectorize/skip-iterations.ll @@ -4,6 +4,14 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f3 ; tests skipping iterations within a VF through break/continue/gotos. +; The main difficulty in vectorizing these loops in test1,test2 and test3 is +; safely speculating that the widened load of A[i] should not fault if the +; scalarized loop does not fault. For example, the +; original load in the scalar loop may not fault, but the last iteration of the +; vectorized load can fault (if it crosses a page boudary for example). +; This last vector iteration is where *one* of the +; scalar iterations lead to the early exit. + ; int test(int *A, int Length) { ; for (int i = 0; i < Length; i++) { ; if (A[i] > 10.0) goto end; @@ -51,7 +59,10 @@ end: ; preds = %end.loopexit, %entr ; } ; return false; ; } -; TODO: Today we do not vectorize this, but we could teach the vectorizer. +; TODO: Today we do not vectorize this, but we could teach the vectorizer, once +; the hard part of proving/speculating A[i:VF - 1] loads does not fault is handled by the +; compiler/hardware. + ; CHECK-LABEL: test2( ; CHECK-NOT: <4 x i32> define i32 @test2(i32* nocapture %A, i32 %Length, i32 %K) { @@ -92,7 +103,8 @@ end: ; preds = %end.loopexit, %entr ; } ; return -1; ; } -; TODO: Today we do not vectorize this, but we could teach the vectorizer. +; TODO: Today we do not vectorize this, but we could teach the vectorizer (once +; we handle the speculation safety of the widened load). ; CHECK-LABEL: test3( ; CHECK-NOT: <4 x i32> define i32 @test3(i32* nocapture %A, i32 %Length, i32 %K) { |
