[llvm-commits] [llvm] r69408 - /llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp

[Dale Johannesen]

Author: johannes
Date: Fri Apr 17 19:09:40 2009
New Revision: 69408

URL: http://llvm.org/viewvc/llvm-project?rev=69408&view=rev
Log:
Inline asm's were still introducing bogus dependencies;
my earlier patch to this code only fixed half of it.


Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp?rev=69408&r1=69407&r2=69408&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp Fri Apr 17 19:09:40 2009
@@ -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.