[llvm] r347524 - [IPSCCP] Use input operand instead of OriginalOp for ssa_copy.

[Florian Hahn via llvm-commits]

Author: fhahn
Date: Sun Nov 25 08:32:02 2018
New Revision: 347524

URL: http://llvm.org/viewvc/llvm-project?rev=347524&view=rev
Log:
[IPSCCP] Use input operand instead of OriginalOp for ssa_copy.

OriginalOp of a Predicate refers to the original IR value,
before renaming. While solving in IPSCCP, we have to use
the operand of the ssa_copy instead, to avoid missing
updates for nested conditions on the same IR value.

Fixes PR39772.

Added:
    llvm/trunk/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/SCCP.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SCCP.cpp?rev=347524&r1=347523&r2=347524&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SCCP.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SCCP.cpp Sun Nov 25 08:32:02 2018
@@ -1171,26 +1171,26 @@ void SCCPSolver::visitCallSite(CallSite
       if (!PI)
         return;
 
+      Value *CopyOf = I->getOperand(0);
       auto *PBranch = dyn_cast<PredicateBranch>(getPredicateInfoFor(I));
       if (!PBranch) {
-        mergeInValue(ValueState[I], I, getValueState(PI->OriginalOp));
+        mergeInValue(ValueState[I], I, getValueState(CopyOf));
         return;
       }
 
-      Value *CopyOf = I->getOperand(0);
       Value *Cond = PBranch->Condition;
 
       // Everything below relies on the condition being a comparison.
       auto *Cmp = dyn_cast<CmpInst>(Cond);
       if (!Cmp) {
-        mergeInValue(ValueState[I], I, getValueState(PI->OriginalOp));
+        mergeInValue(ValueState[I], I, getValueState(CopyOf));
         return;
       }
 
       Value *CmpOp0 = Cmp->getOperand(0);
       Value *CmpOp1 = Cmp->getOperand(1);
       if (CopyOf != CmpOp0 && CopyOf != CmpOp1) {
-        mergeInValue(ValueState[I], I, getValueState(PI->OriginalOp));
+        mergeInValue(ValueState[I], I, getValueState(CopyOf));
         return;
       }
 
@@ -1217,7 +1217,7 @@ void SCCPSolver::visitCallSite(CallSite
         return;
       }
 
-      return (void)mergeInValue(IV, I, getValueState(PBranch->OriginalOp));
+      return (void)mergeInValue(IV, I, getValueState(CopyOf));
     }
   }
 

Added: llvm/trunk/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll?rev=347524&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll (added)
+++ llvm/trunk/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll Sun Nov 25 08:32:02 2018
@@ -0,0 +1,50 @@
+; RUN: opt < %s -ipsccp -S | FileCheck %s
+; RUN: opt < %s -passes=ipsccp -S | FileCheck %s
+
+; Test for PR39772
+; CHECK-LABEL: cleanup:
+; CHECK-NEXT:   %retval.0 = phi i32 [ 0, %if.then ], [ %add, %if.then7 ], [ %add8, %if.else ]
+
+
+%struct.Node = type { %struct.Node*, %struct.Node*, i32 }
+
+define i32 @check(%struct.Node* %node) {
+entry:
+  %cmp = icmp eq %struct.Node* %node, null
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  br label %cleanup
+
+if.end:                                           ; preds = %entry
+  %left = getelementptr inbounds %struct.Node, %struct.Node* %node, i32 0, i32 0
+  %0 = load %struct.Node*, %struct.Node** %left
+  %call = call i32 @check(%struct.Node* %0)
+  %right = getelementptr inbounds %struct.Node, %struct.Node* %node, i32 0, i32 1
+  %1 = load %struct.Node*, %struct.Node** %right
+  %call1 = call i32 @check(%struct.Node* %1)
+  %2 = load %struct.Node*, %struct.Node** %right
+  %height = getelementptr inbounds %struct.Node, %struct.Node* %2, i32 0, i32 2
+  %3 = load i32, i32* %height
+  %cmp3 = icmp ne i32 %3, %call1
+  br i1 %cmp3, label %if.then4, label %if.end5
+
+if.then4:                                         ; preds = %if.end
+  unreachable
+
+if.end5:                                          ; preds = %if.end
+  %cmp6 = icmp sgt i32 %call, %call1
+  br i1 %cmp6, label %if.then7, label %if.else
+
+if.then7:                                         ; preds = %if.end5
+  %add = add nsw i32 %call, 1
+  br label %cleanup
+
+if.else:                                          ; preds = %if.end5
+  %add8 = add nsw i32 %call1, 1
+  br label %cleanup
+
+cleanup:                                          ; preds = %if.else, %if.then7, %if.then
+  %retval.0 = phi i32 [ 0, %if.then ], [ %add, %if.then7 ], [ %add8, %if.else ]
+  ret i32 %retval.0
+}