[llvm] 1745341 - [LoopVectorize] Preserve SCEV

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-04-26T09:43:54+02:00
New Revision: 1745341296495bf50203122cfcc3c4996871590c

URL: https://github.com/llvm/llvm-project/commit/1745341296495bf50203122cfcc3c4996871590c
DIFF: https://github.com/llvm/llvm-project/commit/1745341296495bf50203122cfcc3c4996871590c.diff

LOG: [LoopVectorize] Preserve SCEV

As far as I can tell, LoopVectorize preserves SCEV, mainly by dint
of forgetting the loop being vectorized. We should mark it as
preserved in the pass manager.

This is a very small compile-time improvement.

Differential Revision: https://reviews.llvm.org/D149147

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/test/Transforms/LoopVectorize/novect-lcssa-cfg-invalidation.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 645b62d72ea9f..c9fd816145dfb 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -10610,6 +10610,11 @@ PreservedAnalyses LoopVectorizePass::run(Function &F,
     if (!EnableVPlanNativePath) {
       PA.preserve<LoopAnalysis>();
       PA.preserve<DominatorTreeAnalysis>();
+      PA.preserve<ScalarEvolutionAnalysis>();
+
+#ifdef EXPENSIVE_CHECKS
+      SE.verify();
+#endif
     }
 
     if (Result.MadeCFGChange) {

diff  --git a/llvm/test/Transforms/LoopVectorize/novect-lcssa-cfg-invalidation.ll b/llvm/test/Transforms/LoopVectorize/novect-lcssa-cfg-invalidation.ll
index 24bcfe079ae80..c78e005311ef2 100644
--- a/llvm/test/Transforms/LoopVectorize/novect-lcssa-cfg-invalidation.ll
+++ b/llvm/test/Transforms/LoopVectorize/novect-lcssa-cfg-invalidation.ll
@@ -8,7 +8,7 @@ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 define i32 @novect(ptr %p) {
 
 ; CHECK:           Running pass: LoopVectorizePass on novect
-; CHECK:           Invalidating analysis: ScalarEvolutionAnalysis on novect
+; CHECK-NOT:       Invalidating analysis: ScalarEvolutionAnalysis on novect
 ; CHECK-NOT:       Invalidating analysis: BranchProbabilityAnalysis on novect
 ; CHECK-NOT:       Invalidating analysis: BlockFrequencyAnalysis on novect
 ; CHECK:           Invalidating analysis: DemandedBitsAnalysis on novect