[PATCH] D145395: [SCEV] Also strengthen flags for post-increment.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: reames, nikic, mkazantsev.
Herald added subscribers: StephenFan, javed.absar, hiraditya.
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fhahn requested review of this revision.
Herald added a project: LLVM.

Also strengthen the flags for the post-increment SCEV, as suggested by
@mkazantsev.

Depends on D144050 <https://reviews.llvm.org/D144050>.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D145395

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll


Index: llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
===================================================================
--- llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
+++ llvm/test/Analysis/ScalarEvolution/solve-quadratic-i1.ll
@@ -9,7 +9,7 @@
 ; CHECK-NEXT:    %v0 = phi i16 [ 2, %b0 ], [ %v2, %b1 ]
 ; CHECK-NEXT:    --> {2,+,1}<nuw><nsw><%b1> U: [2,4) S: [2,4) Exits: 3 LoopDispositions: { %b1: Computable }
 ; CHECK-NEXT:    %v1 = phi i16 [ 1, %b0 ], [ %v3, %b1 ]
-; CHECK-NEXT:    --> {1,+,2,+,1}<%b1> U: full-set S: full-set Exits: 3 LoopDispositions: { %b1: Computable }
+; CHECK-NEXT:    --> {1,+,2,+,1}<nsw><%b1> U: [1,-32768) S: [1,-32768) Exits: 3 LoopDispositions: { %b1: Computable }
 ; CHECK-NEXT:    %v2 = add nsw i16 %v0, 1
 ; CHECK-NEXT:    --> {3,+,1}<nuw><nsw><%b1> U: [3,5) S: [3,5) Exits: 4 LoopDispositions: { %b1: Computable }
 ; CHECK-NEXT:    %v3 = add nsw i16 %v1, %v0
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -5670,9 +5670,8 @@
   insertValueToMap(PN, PHISCEV);
 
   if (auto *AR = dyn_cast<SCEVAddRecExpr>(PHISCEV)) {
-    setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR),
-                   (SCEV::NoWrapFlags)(AR->getNoWrapFlags() |
-                                       proveNoWrapViaConstantRanges(AR)));
+    Flags = (SCEV::NoWrapFlags)(Flags | proveNoWrapViaConstantRanges(AR));
+    setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), Flags);
   }
 
   // We can add Flags to the post-inc expression only if we
@@ -5801,9 +5800,9 @@
         insertValueToMap(PN, PHISCEV);
 
         if (auto *AR = dyn_cast<SCEVAddRecExpr>(PHISCEV)) {
-          setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR),
-                         (SCEV::NoWrapFlags)(AR->getNoWrapFlags() |
-                                             proveNoWrapViaConstantRanges(AR)));
+
+          Flags = (SCEV::NoWrapFlags)(Flags | proveNoWrapViaConstantRanges(AR));
+          setNoWrapFlags(const_cast<SCEVAddRecExpr *>(AR), Flags);
         }
 
         // We can add Flags to the post-inc expression only if we


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