[SCCP] Explicitly mark gep as overdefined if ct eval fails

nikic · nikic · commit 0797c184c636 · 2024-09-03T14:39:31.000+02:00
Don't just leave the result as unknown. I think this currently
works out thanks to undef resolution, but the correct thing to
do is set it to overdefined explicitly.
diff --git a/llvm/lib/Transforms/Utils/SCCPSolver.cpp b/llvm/lib/Transforms/Utils/SCCPSolver.cpp
@@ -1655,6 +1655,8 @@ void SCCPInstVisitor::visitGetElementPtrInst(GetElementPtrInst &I) {
 
   if (Constant *C = ConstantFoldInstOperands(&I, Operands, DL))
     markConstant(&I, C);
+  else
+    markOverdefined(&I);
 }
 
 void SCCPInstVisitor::visitAllocaInst(AllocaInst &I) {

Original file line number	Diff line number	Diff line change
`@@ -1655,6 +1655,8 @@ void SCCPInstVisitor::visitGetElementPtrInst(GetElementPtrInst &I) {`
`1655`	`1655`
`1656`	`1656`	`if (Constant *C = ConstantFoldInstOperands(&I, Operands, DL))`
`1657`	`1657`	`markConstant(&I, C);`
	`1658`	`+ else`
	`1659`	`+ markOverdefined(&I);`
`1658`	`1660`	`}`
`1659`	`1661`
`1660`	`1662`	`void SCCPInstVisitor::visitAllocaInst(AllocaInst &I) {`