From 4e33115e5e0b81d515c6f987ff7e869ad6003390 Mon Sep 17 00:00:00 2001
From: Dale Johannesen <dalej@apple.com>
Date: Tue, 7 Jul 2009 23:26:33 +0000
Subject: [PATCH] Operand of asm("call") (the callee function) is represented
 as "X" constraint and "P" modifier on x86.  Make this work. (Change may not
 be sufficient to fix it for non-Darwin, but I'm pretty sure it won't break
 anything.) gcc.apple/asm-block-32.c gcc.apple/asm-block-33.c

llvm-svn: 74967
---
 .../CodeGen/SelectionDAG/TargetLowering.cpp   | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 83357e066009..b9b518afc006 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -2405,11 +2405,24 @@ void TargetLowering::ComputeConstraintToUse(AsmOperandInfo &OpInfo,
   
   // 'X' matches anything.
   if (OpInfo.ConstraintCode == "X" && OpInfo.CallOperandVal) {
+    // Look through bitcasts over functions.  In the context of an asm
+    // argument we don't care about bitcasting function types; the parameters
+    // to the function, if any, will have been handled elsewhere.
+    Value *v = OpInfo.CallOperandVal;
+    ConstantExpr *CE = NULL;
+    while ((CE = dyn_cast<ConstantExpr>(v)) &&
+           CE->getOpcode()==Instruction::BitCast)
+      v = CE->getOperand(0);
+    if (!isa<Function>(v))
+      v = OpInfo.CallOperandVal;
     // Labels and constants are handled elsewhere ('X' is the only thing
-    // that matches labels).
-    if (isa<BasicBlock>(OpInfo.CallOperandVal) ||
-        isa<ConstantInt>(OpInfo.CallOperandVal))
+    // that matches labels).  For Functions, the type here is the type of
+    // the result, which is not what we want to look at; leave them alone
+    // (minus any bitcasts).
+    if (isa<BasicBlock>(v) || isa<ConstantInt>(v) || isa<Function>(v)) {
+      OpInfo.CallOperandVal = v;
       return;
+    }
     
     // Otherwise, try to resolve it to something we know about by looking at
     // the actual operand type.