[llvm] a945ada - [SCEV] Use makeExactNoWrapRegion for constant operands. (NFC) (#223973)

[via llvm-commits]

Author: Florian Hahn
Date: 2026-09-28T10:33:35Z
New Revision: a945adae2eb9236392fbbfe1ab5181f8c073d6f8

URL: https://github.com/llvm/llvm-project/commit/a945adae2eb9236392fbbfe1ab5181f8c073d6f8
DIFF: https://github.com/llvm/llvm-project/commit/a945adae2eb9236392fbbfe1ab5181f8c073d6f8.diff

LOG: [SCEV] Use makeExactNoWrapRegion for constant operands. (NFC) (#223973)

Use makeExactNoWrapRegion when constant is available.

Together with https://github.com/llvm/llvm-project/pull/223969, this
reduces compile-time in SCEV heavy workloads:

stage1-O3: -0.10%
stage1-ReleaseThinLTO: -0.0.9%
stage1-ReleaseLTO-g: -0.08%
stage1-aarch64-O3: -0.09%
stage2-O3: -0.07%

https://llvm-compile-time-tracker.com/compare.php?from=016fa12d18058b83c528f2af859e45df4548034f&to=e2efeaf6a19ac8c53170f2a2b196f3d38268fd32&stat=instructions:u

PR: https://github.com/llvm/llvm-project/pull/223973

Added: 
    

Modified: 
    llvm/lib/Analysis/ScalarEvolution.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index c5e1af4bf060f..ac705f52cd239 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -2473,16 +2473,16 @@ static SCEV::NoWrapFlags StrengthenNoWrapFlags(ScalarEvolution *SE,
 
     // (A <opcode> C) --> (A <opcode> C)<nsw> if the op doesn't sign overflow.
     if (!(SignOrUnsignWrap & SCEV::FlagNSW)) {
-      auto NSWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
-          Opcode, C, OBO::NoSignedWrap);
+      auto NSWRegion =
+          ConstantRange::makeExactNoWrapRegion(Opcode, C, OBO::NoSignedWrap);
       if (NSWRegion.contains(SE->getSignedRange(Ops[1])))
         Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNSW);
     }
 
     // (A <opcode> C) --> (A <opcode> C)<nuw> if the op doesn't unsign overflow.
     if (!(SignOrUnsignWrap & SCEV::FlagNUW)) {
-      auto NUWRegion = ConstantRange::makeGuaranteedNoWrapRegion(
-          Opcode, C, OBO::NoUnsignedWrap);
+      auto NUWRegion =
+          ConstantRange::makeExactNoWrapRegion(Opcode, C, OBO::NoUnsignedWrap);
       if (NUWRegion.contains(SE->getUnsignedRange(Ops[1])))
         Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
     }