[inline asm] Implement mayLoad and mayStore for inline assembly. In general,

the MachineInstr MayLoad/MayLoad flags are based on the tablegen implementation.
For inline assembly, however, we need to compute these based on the constraints.

Revert r166929 as this is no longer needed, but leave the test case in place. 
rdar://12033048 and PR13504

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167040 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 1 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 85103d5750..eacba90f0c 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6128,7 +6128,8 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
   const MDNode *SrcLoc = CS.getInstruction()->getMetadata("srcloc");
   AsmNodeOperands.push_back(DAG.getMDNode(SrcLoc));
 
-  // Remember the HasSideEffect, AlignStack and AsmDialect bits as operand 3.
+  // Remember the HasSideEffect, AlignStack, AsmDialect, MayLoad and MayStore
+  // bits as operand 3.
   unsigned ExtraInfo = 0;
   if (IA->hasSideEffects())
     ExtraInfo |= InlineAsm::Extra_HasSideEffects;
@@ -6136,6 +6137,23 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
     ExtraInfo |= InlineAsm::Extra_IsAlignStack;
   // Set the asm dialect.
   ExtraInfo |= IA->getDialect() * InlineAsm::Extra_AsmDialect;
+
+  // Determine if this InlineAsm MayLoad or MayStore based on the constraints.
+  for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
+    TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
+
+    // Compute the constraint code and ConstraintType to use.
+    TLI.ComputeConstraintToUse(OpInfo, SDValue());
+
+    if (OpInfo.ConstraintType == TargetLowering::C_Memory ||
+        OpInfo.ConstraintType == TargetLowering::C_Other) {
+      if (OpInfo.Type == InlineAsm::isInput)
+        ExtraInfo |= InlineAsm::Extra_MayLoad;
+      else if (OpInfo.Type == InlineAsm::isOutput)
+        ExtraInfo |= InlineAsm::Extra_MayStore;
+    }
+  }
+
   AsmNodeOperands.push_back(DAG.getTargetConstant(ExtraInfo,
                                                   TLI.getPointerTy()));