[llvm] 9099eef - [SCEV] Use getUnsignedOverflowLimit at a site (NFC) (#217395)

[via llvm-commits]

Author: Ramkumar Ramachandra
Date: 2026-08-23T13:21:59+01:00
New Revision: 9099eef1f55537968796f7fdaf30602cf216e79a

URL: https://github.com/llvm/llvm-project/commit/9099eef1f55537968796f7fdaf30602cf216e79a
DIFF: https://github.com/llvm/llvm-project/commit/9099eef1f55537968796f7fdaf30602cf216e79a.diff

LOG: [SCEV] Use getUnsignedOverflowLimit at a site (NFC) (#217395)

Added: 
    

Modified: 
    llvm/lib/Analysis/ScalarEvolution.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index a05b7e9714f01..2be8495c164fc 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -5214,7 +5214,6 @@ ScalarEvolution::proveNoUnsignedWrapViaInduction(const SCEVAddRecExpr *AR) {
     return Result;
 
   const SCEV *Step = AR->getStepRecurrence(*this);
-  unsigned BitWidth = getTypeSizeInBits(AR->getType());
   const Loop *L = AR->getLoop();
 
   // Check whether the backedge-taken count is SCEVCouldNotCompute.
@@ -5244,14 +5243,13 @@ ScalarEvolution::proveNoUnsignedWrapViaInduction(const SCEVAddRecExpr *AR) {
   // start value and the backedge is guarded by a comparison with the post-inc
   // value, the addrec is safe.
   if (isKnownPositive(Step)) {
-    const SCEV *N = getConstant(APInt::getMinValue(BitWidth) -
-                                getUnsignedRangeMax(Step));
-    if (isLoopBackedgeGuardedByCond(L, ICmpInst::ICMP_ULT, AR, N) ||
-        isKnownOnEveryIteration(ICmpInst::ICMP_ULT, AR, N)) {
+    ICmpInst::Predicate Pred;
+    const SCEV *OverflowLimit =
+        getUnsignedOverflowLimitForStep(Step, &Pred, this);
+    if (isLoopBackedgeGuardedByCond(L, Pred, AR, OverflowLimit) ||
+        isKnownOnEveryIteration(Pred, AR, OverflowLimit))
       Result = setFlags(Result, SCEV::FlagNUW);
-    }
   }
-
   return Result;
 }