Implement negation of longs efficiently. For this testcase:
long %test(long %X) {
%Y = sub long 0, %X
ret long %Y
}
We used to generate:
test:
sub %ESP, 4
mov DWORD PTR [%ESP], %ESI
mov %ECX, DWORD PTR [%ESP + 8]
mov %ESI, DWORD PTR [%ESP + 12]
mov %EAX, 0
mov %EDX, 0
sub %EAX, %ECX
sbb %EDX, %ESI
mov %ESI, DWORD PTR [%ESP]
add %ESP, 4
ret
Now we generate:
test:
mov %EAX, DWORD PTR [%ESP + 4]
mov %EDX, DWORD PTR [%ESP + 8]
neg %EAX
adc %EDX, 0
neg %EDX
ret
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12681 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed