[InstCombine] Merge debug locations when folding through a phi node
If all the operands to a phi node are of the same operation, instcombine
will try to pull them through the phi node, combining them into a single
operation. When it does this, the debug location of the operation should
be the merged debug locations of the phi node arguments.
Patch 2 of 8 for D26256. Folding of a binary operation.
Differential Revision: https://reviews.llvm.org/D26256
llvm-svn: 289679
diff --git a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
index 675a5d1..91bfe6c 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp
@@ -18,11 +18,27 @@
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/IR/DebugInfo.h"
using namespace llvm;
using namespace llvm::PatternMatch;
#define DEBUG_TYPE "instcombine"
+/// The PHI arguments will be folded into a single operation with a PHI node
+/// as input. The debug location of the single operation will be the merged
+/// locations of the original PHI node arguments.
+DebugLoc InstCombiner::PHIArgMergedDebugLoc(PHINode &PN) {
+ auto *FirstInst = cast<Instruction>(PN.getIncomingValue(0));
+ DILocation *Loc = FirstInst->getDebugLoc();
+
+ for (unsigned i = 1; i != PN.getNumIncomingValues(); ++i) {
+ auto *I = cast<Instruction>(PN.getIncomingValue(i));
+ Loc = DILocation::getMergedLocation(Loc, I->getDebugLoc());
+ }
+
+ return Loc;
+}
+
/// If we have something like phi [add (a,b), add(a,c)] and if a/b/c and the
/// adds all have a single use, turn this into a phi and a single binop.
Instruction *InstCombiner::FoldPHIArgBinOpIntoPHI(PHINode &PN) {
@@ -114,7 +130,7 @@
for (unsigned i = 1, e = PN.getNumIncomingValues(); i != e; ++i)
NewBinOp->andIRFlags(PN.getIncomingValue(i));
- NewBinOp->setDebugLoc(FirstInst->getDebugLoc());
+ NewBinOp->setDebugLoc(PHIArgMergedDebugLoc(PN));
return NewBinOp;
}