[SVE][AArch64] Improve specificity of vectorization legality TypeSize test

[joechrisellis]

Summary

The test was using -O2, where -loop-vectorize will suffice.

[fpetrogalli]

LGTM - but can you explain in the commit why you are doing this? In particular, can you state that the test case still fails without the fix that removed the warning?

[joechrisellis]

@fpetrogalli sure!

The original patch was D89798, which fixed a TypeSize warning in loop vectorization legality. The test being modified in this patch defends against that warning. So:

• without D89798, a TypeSize warning will fire, so this test will fail.
• with D89798, a TypeSize warning will not fire, so this test will pass.

It turns out that -O2 is probably not the best flag for this test; the passes performed by -O2 are not guaranteed to remain consistent, so this test could fail if this changes in the future. Since the TypeSize warning arose in loop vectorization legality, it suffices to use -loop-vectorize here instead of -O2.

I have also tested this patch. It fails without D89798 applied, but passes with D89798 applied, so it is functionally equivalent to the old test but more future proof.

[fpetrogalli]

LGTM, thanks for explaining!

llvm/test/Transforms/LoopVectorize/AArch64/sve-scalable-load-in-loop.ll

-; RUN: opt -S -O2 -mtriple=aarch64-linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
+; RUN: opt -S -loop-vectorize -mtriple=aarch64-linux-gnu -mattr=+sve < %s 2>%t | FileCheck %s
 ; RUN: FileCheck --check-prefix=WARN --allow-empty %s <%t
 
 ; This test is checking that a scalable load inside a loop does not trigger a
 ; TypeSize error in the loop vectorization legality analysis. It is possible for
 ; a scalable/vector load to appear inside a loop at vectorization legality
 ; analysis if, for example, the ACLE are used. If we encounter a scalable/vector
 ; load, it should not be considered for analysis, and we should not see a
 ; TypeSize error.