Inline asm's were still introducing bogus dependencies;
my earlier patch to this code only fixed half of it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69408 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index 5204113..b20f061 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -5111,7 +5111,9 @@
/// ConstraintOperands - Information about all of the constraints.
std::vector<SDISelAsmOperandInfo> ConstraintOperands;
- SDValue Chain = getRoot();
+ // We won't need to flush pending loads if this asm doesn't touch
+ // memory and is nonvolatile.
+ SDValue Chain = IA->hasSideEffects() ? getRoot() : DAG.getRoot();
SDValue Flag;
std::set<unsigned> OutputRegs, InputRegs;
@@ -5122,6 +5124,10 @@
ConstraintInfos = IA->ParseConstraints();
bool hasMemory = hasInlineAsmMemConstraint(ConstraintInfos, TLI);
+ // Flush pending loads if this touches memory (includes clobbering it).
+ // It's possible this is overly conservative.
+ if (hasMemory)
+ Chain = getRoot();
unsigned ArgNo = 0; // ArgNo - The argument of the CallInst.
unsigned ResNo = 0; // ResNo - The result number of the next output.