[PATCH] D110892: [SCEV] Remove invariant requirement from isSCEVExprNeverPoison

[Philip Reames via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG24cde2f6023a: [SCEV] Remove invariant requirement from isSCEVExprNeverPoison (authored by reames).

Changed prior to commit:
  https://reviews.llvm.org/D110892?vs=376395&id=376647#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D110892/new/

https://reviews.llvm.org/D110892

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/flags-from-poison.ll


Index: llvm/test/Analysis/ScalarEvolution/flags-from-poison.ll
===================================================================
--- llvm/test/Analysis/ScalarEvolution/flags-from-poison.ll
+++ llvm/test/Analysis/ScalarEvolution/flags-from-poison.ll
@@ -142,9 +142,9 @@
 ; CHECK-NEXT:    %i.next = add nuw i32 %i, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><%loop> U: [1,0) S: [1,0) Exits: <<Unknown>> LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %of_interest = add nuw nsw i32 %i.next, %offset
-; CHECK-NEXT:    --> ({1,+,1}<nuw><%loop> + %offset) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> ({1,+,1}<nuw><%loop> + %offset)<nuw><nsw> U: [1,0) S: [1,0) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %gep2 = getelementptr i32, i32* %input, i32 %of_interest
-; CHECK-NEXT:    --> ((4 * (sext i32 ({1,+,1}<nuw><%loop> + %offset) to i64))<nsw> + %input) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> ((4 * ((sext i32 {1,+,1}<nuw><%loop> to i64) + (sext i32 %offset to i64))<nsw>)<nsw> + %input) U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @test-add-scope-bound
 ; CHECK-NEXT:  Loop %loop: Unpredictable backedge-taken count.
 ; CHECK-NEXT:  Loop %loop: Unpredictable max backedge-taken count.
Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6582,15 +6582,11 @@
   // instructions can map to the same SCEV. If we apply NSW or NUW from I to
   // the SCEV, we must guarantee no wrapping for that SCEV also when it is
   // derived from other instructions that map to the same SCEV. We cannot make
-  // that guarantee for cases where I is not executed. So we need to find the
-  // loop that I is considered in relation to and prove that I is executed for
-  // every iteration of that loop. That implies that the value that I
-  // calculates does not wrap anywhere in the loop, so then we can apply the
-  // flags to the SCEV.
-  //
-  // We check isLoopInvariant to disambiguate in case we are adding recurrences
-  // from different loops, so that we know which loop to prove that I is
-  // executed in.
+  // that guarantee for cases where I is not executed. So we need to find a
+  // upper bound on the defining scope for the SCEV, and prove that I is
+  // executed every time we enter that scope.  When the bounding scope is a
+  // loop (the common case), this is equivalent to proving I executes on every
+  // iteration of that loop.
   for (const Use &Op : I->operands()) {
     // I could be an extractvalue from a call to an overflow intrinsic.
     // TODO: We can do better here in some cases.
@@ -6598,15 +6594,7 @@
       return false;
     const SCEV *OpS = getSCEV(Op);
     if (auto *AddRecS = dyn_cast<SCEVAddRecExpr>(OpS)) {
-      const bool AllOtherOpsLoopInvariant =
-        llvm::all_of(I->operands(), [&](const Use &Op2) -> bool {
-          if (Op.getOperandNo() == Op2.getOperandNo())
-            return true;
-          const SCEV *OtherOp = getSCEV(Op2);
-          return isLoopInvariant(OtherOp, AddRecS->getLoop());
-        });
-      if (AllOtherOpsLoopInvariant &&
-          isGuaranteedToExecuteForEveryIteration(I, AddRecS->getLoop()))
+      if (isGuaranteedToExecuteForEveryIteration(I, AddRecS->getLoop()))
         return true;
     }
   }


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