Reapply "Fix crash on inline asm with 64bit matching input in 32bit GPR"

This reapplies commit r338206 reverted by r338214 since the bug that
r338206 uncovered has been fixed in r338268.

Add support for inline assembly with matching input operand that do not
naturally go in the register class it is constrained to (eg. double in a
32-bit GPR). Note that regular input is already handled by existing
code.

llvm-svn: 338269

1 files changed, 23 insertions, 9 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index abf9a216f3a..c12d1a7a88d 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -7198,10 +7198,11 @@ static SDValue getAddressForMemoryInput(SDValue Chain, const SDLoc &Location,
 /// uses features that we can't model on machineinstrs, we have SDISel do the
 /// allocation.  This produces generally horrible, but correct, code.
 ///
-///   OpInfo describes the operand.
+///   OpInfo describes the operand
+///   RefOpInfo describes the matching operand if any, the operand otherwise
 static void GetRegistersForValue(SelectionDAG &DAG, const TargetLowering &TLI,
-                                 const SDLoc &DL,
-                                 SDISelAsmOperandInfo &OpInfo) {
+                                 const SDLoc &DL, SDISelAsmOperandInfo &OpInfo,
+                                 SDISelAsmOperandInfo &RefOpInfo) {
   LLVMContext &Context = *DAG.getContext();
 
   MachineFunction &MF = DAG.getMachineFunction();
@@ -7211,8 +7212,8 @@ static void GetRegistersForValue(SelectionDAG &DAG, const TargetLowering &TLI,
   // If this is a constraint for a single physreg, or a constraint for a
   // register class, find it.
   std::pair<unsigned, const TargetRegisterClass *> PhysReg =
-      TLI.getRegForInlineAsmConstraint(&TRI, OpInfo.ConstraintCode,
-                                       OpInfo.ConstraintVT);
+      TLI.getRegForInlineAsmConstraint(&TRI, RefOpInfo.ConstraintCode,
+                                       RefOpInfo.ConstraintVT);
 
   unsigned NumRegs = 1;
   if (OpInfo.ConstraintVT != MVT::Other) {
@@ -7254,6 +7255,11 @@ static void GetRegistersForValue(SelectionDAG &DAG, const TargetLowering &TLI,
     NumRegs = TLI.getNumRegisters(Context, OpInfo.ConstraintVT);
   }
 
+  // No need to allocate a matching input constraint since the constraint it's
+  // matching to has already been allocated.
+  if (OpInfo.isMatchingInputConstraint())
+    return;
+
   MVT RegVT;
   EVT ValueVT = OpInfo.ConstraintVT;
 
@@ -7502,19 +7508,27 @@ void SelectionDAGBuilder::visitInlineAsm(ImmutableCallSite CS) {
 
     // If this constraint is for a specific register, allocate it before
     // anything else.
-    if (OpInfo.ConstraintType == TargetLowering::C_Register)
-      GetRegistersForValue(DAG, TLI, getCurSDLoc(), OpInfo);
+    SDISelAsmOperandInfo &RefOpInfo =
+        OpInfo.isMatchingInputConstraint()
+            ? ConstraintOperands[OpInfo.getMatchedOperand()]
+            : ConstraintOperands[i];
+    if (RefOpInfo.ConstraintType == TargetLowering::C_Register)
+      GetRegistersForValue(DAG, TLI, getCurSDLoc(), OpInfo, RefOpInfo);
   }
 
   // Third pass - Loop over all of the operands, assigning virtual or physregs
   // to register class operands.
   for (unsigned i = 0, e = ConstraintOperands.size(); i != e; ++i) {
     SDISelAsmOperandInfo &OpInfo = ConstraintOperands[i];
+    SDISelAsmOperandInfo &RefOpInfo =
+        OpInfo.isMatchingInputConstraint()
+            ? ConstraintOperands[OpInfo.getMatchedOperand()]
+            : ConstraintOperands[i];
 
     // C_Register operands have already been allocated, Other/Memory don't need
     // to be.
-    if (OpInfo.ConstraintType == TargetLowering::C_RegisterClass)
-      GetRegistersForValue(DAG, TLI, getCurSDLoc(), OpInfo);
+    if (RefOpInfo.ConstraintType == TargetLowering::C_RegisterClass)
+      GetRegistersForValue(DAG, TLI, getCurSDLoc(), OpInfo, RefOpInfo);
   }
 
   // AsmNodeOperands - The operands for the ISD::INLINEASM node.