[llvm] 3716125 - [SCEV] Reuse Accum variable when handling GEP flags

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-05-02T11:03:38+02:00
New Revision: 371612500afa4ffcdd411f585a427edb5cd037f7

URL: https://github.com/llvm/llvm-project/commit/371612500afa4ffcdd411f585a427edb5cd037f7
DIFF: https://github.com/llvm/llvm-project/commit/371612500afa4ffcdd411f585a427edb5cd037f7.diff

LOG: [SCEV] Reuse Accum variable when handling GEP flags

The GEP minus the base pointer (which is the pre-inc addrec) is
exactly the Accum value that was already calculated.

Added: 
    

Modified: 
    llvm/lib/Analysis/ScalarEvolution.cpp

Removed: 
    


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diff  --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 306090f3eb11c..ba3a6092b62cc 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -5838,9 +5838,7 @@ const SCEV *ScalarEvolution::createAddRecFromPHI(PHINode *PN) {
           // indices form a positive value.
           if (GEP->isInBounds() && GEP->getOperand(0) == PN) {
             Flags = setFlags(Flags, SCEV::FlagNW);
-
-            const SCEV *Ptr = getSCEV(GEP->getPointerOperand());
-            if (isKnownPositive(getMinusSCEV(getSCEV(GEP), Ptr)))
+            if (isKnownPositive(Accum))
               Flags = setFlags(Flags, SCEV::FlagNUW);
           }