[PATCH] D88276: [IsKnownNonZero] Handle the case with non-constant phi nodes

[Serguei Katkov via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG297ec6113046: [IsKnownNonZero] Handle the case with non-constant phi nodes (authored by skatkov).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D88276/new/

https://reviews.llvm.org/D88276

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Transforms/InstCombine/phi.ll


Index: llvm/test/Transforms/InstCombine/phi.ll
===================================================================
--- llvm/test/Transforms/InstCombine/phi.ll
+++ llvm/test/Transforms/InstCombine/phi.ll
@@ -1056,6 +1056,35 @@
   ret i1 %cmp1
 }
 
+define i1 @phi_allnonzerononconstant(i1 %c, i32 %a, i32* nonnull %b1, i32* nonnull %b2) {
+; CHECK-LABEL: @phi_allnonzerononconstant(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK:       if.then:
+; CHECK-NEXT:    br label [[IF_END:%.*]]
+; CHECK:       if.else:
+; CHECK-NEXT:    call void @dummy()
+; CHECK-NEXT:    br label [[IF_END]]
+; CHECK:       if.end:
+; CHECK-NEXT:    ret i1 false
+;
+entry:
+  br i1 %c, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  call void @dummy()
+
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %x.0 = phi i32* [ %b1, %if.then ], [ %b2, %if.else ]
+  %cmp1 = icmp eq i32* %x.0, null
+  ret i1 %cmp1
+}
+
 declare void @dummy()
 
 define i1 @phi_knownnonzero_eq(i32 %n, i32 %s, i32* nocapture readonly %P) {
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -2561,11 +2561,16 @@
         }
       }
     }
-    // Check if all incoming values are non-zero constant.
-    bool AllNonZeroConstants = llvm::all_of(PN->operands(), [](Value *V) {
-      return isa<ConstantInt>(V) && !cast<ConstantInt>(V)->isZero();
+    // Check if all incoming values are non-zero using recursion.
+    Query RecQ = Q;
+    unsigned NewDepth = std::max(Depth, MaxAnalysisRecursionDepth - 1);
+    bool AllNonZero = llvm::all_of(PN->operands(), [&](const Use &U) {
+      if (U.get() == PN)
+        return true;
+      RecQ.CxtI = PN->getIncomingBlock(U)->getTerminator();
+      return isKnownNonZero(U.get(), DemandedElts, NewDepth, RecQ);
     });
-    if (AllNonZeroConstants)
+    if (AllNonZero)
       return true;
   }
   // ExtractElement


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