Two more improvements for null pointer handling: storing a null pointer
and passing a null pointer into a function.
For this testcase:
void %test(int** %X) {
store int* null, int** %X
call void %test(int** null)
ret void
}
we now generate this:
test:
sub %ESP, 12
mov %EAX, DWORD PTR [%ESP + 16]
mov DWORD PTR [%EAX], 0
mov DWORD PTR [%ESP], 0
call test
add %ESP, 12
ret
instead of this:
test:
sub %ESP, 12
mov %EAX, DWORD PTR [%ESP + 16]
mov %ECX, 0
mov DWORD PTR [%EAX], %ECX
mov %EAX, 0
mov DWORD PTR [%ESP], %EAX
call test
add %ESP, 12
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13558 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index 9306b2c..e0e641e 100644
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -1500,6 +1500,9 @@
unsigned Val = cast<ConstantInt>(Args[i].Val)->getRawValue();
addRegOffset(BuildMI(BB, X86::MOV32mi, 5),
X86::ESP, ArgOffset).addImm(Val);
+ } else if (Args[i].Val && isa<ConstantPointerNull>(Args[i].Val)) {
+ addRegOffset(BuildMI(BB, X86::MOV32mi, 5),
+ X86::ESP, ArgOffset).addImm(0);
} else {
ArgReg = Args[i].Val ? getReg(Args[i].Val) : Args[i].Reg;
addRegOffset(BuildMI(BB, X86::MOV32mr, 5),
@@ -2984,13 +2987,19 @@
X86::MOV8mi, X86::MOV16mi, X86::MOV32mi
};
unsigned Opcode = Opcodes[Class];
- if (AllocaFrameIdx != ~0U) {
+ if (AllocaFrameIdx != ~0U)
addFrameReference(BuildMI(BB, Opcode, 5), AllocaFrameIdx).addImm(Val);
- } else {
+ else
addFullAddress(BuildMI(BB, Opcode, 5),
BaseReg, Scale, IndexReg, Disp).addImm(Val);
- }
}
+ } else if (isa<ConstantPointerNull>(I.getOperand(0))) {
+ if (AllocaFrameIdx != ~0U)
+ addFrameReference(BuildMI(BB, X86::MOV32mi, 5), AllocaFrameIdx).addImm(0);
+ else
+ addFullAddress(BuildMI(BB, X86::MOV32mi, 5),
+ BaseReg, Scale, IndexReg, Disp).addImm(0);
+
} else if (ConstantBool *CB = dyn_cast<ConstantBool>(I.getOperand(0))) {
if (AllocaFrameIdx != ~0U)
addFrameReference(BuildMI(BB, X86::MOV8mi, 5),