Fix a codegen fault in which log2 or exp2 could be dead-code eliminated even though they could have sideeffects.
Only allow log2/exp2 to be converted to an intrinsic if they are declared "readnone".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151807 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 0038633..4a6f409 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5627,7 +5627,8 @@
(LibInfo->has(LibFunc::log2l) && Name == "log2l")) {
if (I.getNumArgOperands() == 1 && // Basic sanity checks.
I.getArgOperand(0)->getType()->isFloatingPointTy() &&
- I.getType() == I.getArgOperand(0)->getType()) {
+ I.getType() == I.getArgOperand(0)->getType() &&
+ I.onlyReadsMemory()) {
SDValue Tmp = getValue(I.getArgOperand(0));
setValue(&I, DAG.getNode(ISD::FLOG2, getCurDebugLoc(),
Tmp.getValueType(), Tmp));
@@ -5638,7 +5639,8 @@
(LibInfo->has(LibFunc::exp2l) && Name == "exp2l")) {
if (I.getNumArgOperands() == 1 && // Basic sanity checks.
I.getArgOperand(0)->getType()->isFloatingPointTy() &&
- I.getType() == I.getArgOperand(0)->getType()) {
+ I.getType() == I.getArgOperand(0)->getType() &&
+ I.onlyReadsMemory()) {
SDValue Tmp = getValue(I.getArgOperand(0));
setValue(&I, DAG.getNode(ISD::FEXP2, getCurDebugLoc(),
Tmp.getValueType(), Tmp));