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[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.

llvm-svn: 347524
This commit is contained in:
Florian Hahn 2018-11-25 16:32:02 +00:00
parent 04435677d0
commit 6615a7132a
2 changed files with 55 additions and 5 deletions
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10
llvm/lib/Transforms/Scalar/SCCP.cpp
View File

@ -1171,26 +1171,26 @@ void SCCPSolver::visitCallSite(CallSite CS) {
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 CS) {
return;
}
return (void)mergeInValue(IV, I, getValueState(PBranch->OriginalOp));
return (void)mergeInValue(IV, I, getValueState(CopyOf));
}
}

50
llvm/test/Transforms/SCCP/ipsccp-ssa-copy-nested-conds.ll Normal file
View File

@ -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
}