mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-12-21 11:10:12 +00:00
268cfea6bc
use a SUB instruction instead of an ADD, because -128 can be encoded in an 8-bit signed immediate field, while +128 can't be. This avoids the need for a 32-bit immediate field in this case. A similar optimization applies to 64-bit adds with 0x80000000, with the 32-bit signed immediate field. To support this, teach tablegen how to handle 64-bit constants. llvm-svn: 57663
12 lines
273 B
LLVM
12 lines
273 B
LLVM
; RUN: llvm-as < %s | llc -march=x86 > %t
|
|
; RUN: not grep add %t
|
|
; RUN: grep subl %t | count 1
|
|
|
|
; The immediate can be encoded in a smaller way if the
|
|
; instruction is a sub instead of an add.
|
|
|
|
define i32 @foo(i32 inreg %a) nounwind {
|
|
%b = add i32 %a, 128
|
|
ret i32 %b
|
|
}
|