[llvm] 6d86a8a - LAA: scope responsibility of isNoWrapAddRec (NFC) (#127479)

[via llvm-commits]

Author: Ramkumar Ramachandra
Date: 2025-02-17T16:58:09Z
New Revision: 6d86a8a1a12856955aba5e06a6552ddafaaa208f

URL: https://github.com/llvm/llvm-project/commit/6d86a8a1a12856955aba5e06a6552ddafaaa208f
DIFF: https://github.com/llvm/llvm-project/commit/6d86a8a1a12856955aba5e06a6552ddafaaa208f.diff

LOG: LAA: scope responsibility of isNoWrapAddRec (NFC) (#127479)

Free isNoWrapAddRec from the AddRec check, and rename it to isNoWrapGEP.

Added: 
    

Modified: 
    llvm/lib/Analysis/LoopAccessAnalysis.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 7d6dbd51a404d..23bfd9989469a 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -793,7 +793,8 @@ class AccessAnalysis {
 
 } // end anonymous namespace
 
-/// Try to compute the stride for \p AR. Used by getPtrStride.
+/// Try to compute a constant stride for \p AR. Used by getPtrStride and
+/// isNoWrap.
 static std::optional<int64_t>
 getStrideFromAddRec(const SCEVAddRecExpr *AR, const Loop *Lp, Type *AccessTy,
                     Value *Ptr, PredicatedScalarEvolution &PSE) {
@@ -835,16 +836,24 @@ getStrideFromAddRec(const SCEVAddRecExpr *AR, const Loop *Lp, Type *AccessTy,
   return Stride;
 }
 
-static bool isNoWrapAddRec(Value *Ptr, const SCEVAddRecExpr *AR,
-                           PredicatedScalarEvolution &PSE, const Loop *L);
+static bool isNoWrapGEP(Value *Ptr, PredicatedScalarEvolution &PSE,
+                        const Loop *L);
 
-/// Check whether a pointer address cannot wrap.
+/// Check whether \p AR is a non-wrapping AddRec, or if \p Ptr is a non-wrapping
+/// GEP.
 static bool isNoWrap(PredicatedScalarEvolution &PSE, const SCEVAddRecExpr *AR,
                      Value *Ptr, Type *AccessTy, const Loop *L, bool Assume,
                      std::optional<int64_t> Stride = std::nullopt) {
+  // FIXME: This should probably only return true for NUW.
+  if (AR->getNoWrapFlags(SCEV::NoWrapMask))
+    return true;
+
+  if (PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW))
+    return true;
+
   // The address calculation must not wrap. Otherwise, a dependence could be
   // inverted.
-  if (isNoWrapAddRec(Ptr, AR, PSE, L))
+  if (isNoWrapGEP(Ptr, PSE, L))
     return true;
 
   // An nusw getelementptr that is an AddRec cannot wrap. If it would wrap,
@@ -1445,18 +1454,9 @@ void AccessAnalysis::processMemAccesses() {
   }
 }
 
-/// Return true if an AddRec pointer \p Ptr is unsigned non-wrapping,
-/// i.e. monotonically increasing/decreasing.
-static bool isNoWrapAddRec(Value *Ptr, const SCEVAddRecExpr *AR,
-                           PredicatedScalarEvolution &PSE, const Loop *L) {
-
-  // FIXME: This should probably only return true for NUW.
-  if (AR->getNoWrapFlags(SCEV::NoWrapMask))
-    return true;
-
-  if (PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW))
-    return true;
-
+/// Check whether \p Ptr is non-wrapping GEP.
+static bool isNoWrapGEP(Value *Ptr, PredicatedScalarEvolution &PSE,
+                        const Loop *L) {
   // Scalar evolution does not propagate the non-wrapping flags to values that
   // are derived from a non-wrapping induction variable because non-wrapping
   // could be flow-sensitive.