Handle i1/i8/i16 constant integer arguments to calls by prepromoting them.
Before we would bail out on i1 arguments all together, now we just bail on
non-constant ones. Also, we used to emit extraneous code. e.g. test12 was:
movb $0, %al
movzbl %al, %edi
callq _test12
and test13 was:
movb $0, %al
xorl %edi, %edi
movb %al, 7(%rsp)
callq _test13f
Now we get:
movl $0, %edi
callq _test12
and:
movl $0, %edi
callq _test13f
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129751 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 77e67a1..8c46d7f 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -1457,8 +1457,7 @@
// Handle only C and fastcc calling conventions for now.
ImmutableCallSite CS(CI);
CallingConv::ID CC = CS.getCallingConv();
- if (CC != CallingConv::C &&
- CC != CallingConv::Fast &&
+ if (CC != CallingConv::C && CC != CallingConv::Fast &&
CC != CallingConv::X86_FastCall)
return false;
@@ -1517,9 +1516,7 @@
ArgFlags.reserve(CS.arg_size());
for (ImmutableCallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
i != e; ++i) {
- unsigned Arg = getRegForValue(*i);
- if (Arg == 0)
- return false;
+ Value *ArgVal = *i;
ISD::ArgFlagsTy Flags;
unsigned AttrInd = i - CS.arg_begin() + 1;
if (CS.paramHasAttr(AttrInd, Attribute::SExt))
@@ -1527,6 +1524,23 @@
if (CS.paramHasAttr(AttrInd, Attribute::ZExt))
Flags.setZExt();
+ // 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 (ConstantInt *CI = dyn_cast<ConstantInt>(ArgVal)) {
+ if (CI->getBitWidth() == 1 || CI->getBitWidth() == 8 ||
+ CI->getBitWidth() == 16) {
+ if (Flags.isSExt())
+ ArgVal = ConstantExpr::getSExt(CI,Type::getInt32Ty(CI->getContext()));
+ else
+ ArgVal = ConstantExpr::getZExt(CI,Type::getInt32Ty(CI->getContext()));
+ }
+ }
+
+ unsigned Arg = getRegForValue(ArgVal);
+ if (Arg == 0)
+ return false;
+
// FIXME: Only handle *easy* calls for now.
if (CS.paramHasAttr(AttrInd, Attribute::InReg) ||
CS.paramHasAttr(AttrInd, Attribute::StructRet) ||
@@ -1534,7 +1548,7 @@
CS.paramHasAttr(AttrInd, Attribute::ByVal))
return false;
- const Type *ArgTy = (*i)->getType();
+ const Type *ArgTy = ArgVal->getType();
MVT ArgVT;
if (!isTypeLegal(ArgTy, ArgVT))
return false;
@@ -1542,7 +1556,7 @@
Flags.setOrigAlign(OriginalAlignment);
Args.push_back(Arg);
- ArgVals.push_back(*i);
+ ArgVals.push_back(ArgVal);
ArgVTs.push_back(ArgVT);
ArgFlags.push_back(Flags);
}
@@ -1552,9 +1566,8 @@
CCState CCInfo(CC, false, TM, ArgLocs, I->getParent()->getContext());
// Allocate shadow area for Win64
- if (Subtarget->isTargetWin64()) {
+ if (Subtarget->isTargetWin64())
CCInfo.AllocateStack(32, 8);
- }
CCInfo.AnalyzeCallOperands(ArgVTs, ArgFlags, CC_X86);