[llvm] [SCCPSolver] Move getValueState to later (PR #175307)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-function-specialization

Author: None (aokblast)

<details>
<summary>Changes</summary>

If the IV is overDefined, there is no reason for us to init V0State.

---
Full diff: https://github.com/llvm/llvm-project/pull/175307.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Utils/SCCPSolver.cpp (+2-3) 


``````````diff
diff --git a/llvm/lib/Transforms/Utils/SCCPSolver.cpp b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
index 021bf0618754a..b5b7a7fbb587b 100644
--- a/llvm/lib/Transforms/Utils/SCCPSolver.cpp
+++ b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
@@ -1661,14 +1661,13 @@ void SCCPInstVisitor::visitSelectInst(SelectInst &I) {
 
 // Handle Unary Operators.
 void SCCPInstVisitor::visitUnaryOperator(Instruction &I) {
-  ValueLatticeElement V0State = getValueState(I.getOperand(0));
-
   ValueLatticeElement &IV = ValueState[&I];
   // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
   // discover a concrete value later.
   if (IV.isOverdefined())
     return (void)markOverdefined(&I);
 
+  ValueLatticeElement V0State = getValueState(I.getOperand(0));
   // If something is unknown/undef, wait for it to resolve.
   if (V0State.isUnknownOrUndef())
     return;
@@ -1687,13 +1686,13 @@ void SCCPInstVisitor::visitFreezeInst(FreezeInst &I) {
   if (I.getType()->isStructTy())
     return (void)markOverdefined(&I);
 
-  ValueLatticeElement V0State = getValueState(I.getOperand(0));
   ValueLatticeElement &IV = ValueState[&I];
   // resolvedUndefsIn might mark I as overdefined. Bail out, even if we would
   // discover a concrete value later.
   if (IV.isOverdefined())
     return (void)markOverdefined(&I);
 
+  ValueLatticeElement V0State = getValueState(I.getOperand(0));
   // If something is unknown/undef, wait for it to resolve.
   if (V0State.isUnknownOrUndef())
     return;

``````````

</details>


https://github.com/llvm/llvm-project/pull/175307