Emit immediate call arguments locally to save stack size when compiling with -O0

lib/Target/X86/X86FastISel.cpp

Index: lib/Target/X86/X86FastISel.cpp
===================================================================
--- lib/Target/X86/X86FastISel.cpp	(revision 136475)
+++ lib/Target/X86/X86FastISel.cpp	(working copy)
@@ -1565,10 +1565,12 @@
     if (CS.paramHasAttr(AttrInd, Attribute::Nest))
       Flags.setNest();
 
-    // If this is an i1/i8/i16 argument, promote to i32 to avoid an extra
-    // instruction.  This is safe because it is common to all fastisel supported
-    // calling conventions on x86.
+    unsigned ArgReg;
+    MVT ArgVT;
     if (ConstantInt *CI = dyn_cast<ConstantInt>(ArgVal)) {
+      // If this is an i1/i8/i16 argument, promote to i32 to avoid an extra
+      // instruction.  This is safe because it is common to all fastisel
+      // supported calling conventions on x86.
       if (CI->getBitWidth() == 1 || CI->getBitWidth() == 8 ||
           CI->getBitWidth() == 16) {
         if (Flags.isSExt())
@@ -1576,20 +1578,25 @@
         else
           ArgVal = ConstantExpr::getZExt(CI,Type::getInt32Ty(CI->getContext()));
       }
-    }
 
-    unsigned ArgReg;
-
+      // Emit immediate arguments for the call locally to avoid spilling.
+      if (!isTypeLegal(ArgVal->getType(), ArgVT)) return false;
+      uint64_t val;
+      if (Flags.isSExt())
+        val = CI->getSExtValue();
+      else
+        val = CI->getZExtValue();
+        ArgReg = FastEmit_i(ArgVT, ArgVT, ISD::Constant, val);
+      //      ArgReg = getRegForValue(ArgVal);

[nlewycky, 2011/08/01 20:49:28]

Don't send out a patch with a commented-out line.

[krasin, 2011/08/01 20:55:37]

Shame on me!
Done.

     // Passing bools around ends up doing a trunc to i1 and passing it.
     // Codegen this as an argument + "and 1".
-    if (ArgVal->getType()->isIntegerTy(1) && isa<TruncInst>(ArgVal) &&
+    } else if (ArgVal->getType()->isIntegerTy(1) && isa<TruncInst>(ArgVal) &&
         cast<TruncInst>(ArgVal)->getParent() == I->getParent() &&
         ArgVal->hasOneUse()) {
       ArgVal = cast<TruncInst>(ArgVal)->getOperand(0);
       ArgReg = getRegForValue(ArgVal);
       if (ArgReg == 0) return false;
 
-      MVT ArgVT;
       if (!isTypeLegal(ArgVal->getType(), ArgVT)) return false;
 
       ArgReg = FastEmit_ri(ArgVT, ArgVT, ISD::AND, ArgReg,
@@ -1601,7 +1608,6 @@
     if (ArgReg == 0) return false;
 
     Type *ArgTy = ArgVal->getType();
-    MVT ArgVT;
     if (!isTypeLegal(ArgTy, ArgVT))
       return false;
     if (ArgVT == MVT::x86mmx)