llvm-6502/test/CodeGen/X86/fast-isel-sext.ll
Rafael Espindola 7bdc1cb690 Use sext in fast isel.
Fast isel used to zero extends immediates to 64 bits. This normally goes
unnoticed because the value is truncated to 32 bits for output.

Two cases were it is noticed:

* We fail to use smaller encodings.
* If the original constant was smaller than i32.

In the tests using i1 constants, codegen would change to use -1, which is fine
(and matches what regular isel does) since only the lowest bit is then used.

Instead, this patch then changes the ir to use i8 constants, which looks more
like what clang produces.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234249 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-06 22:29:07 +00:00

10 lines
259 B
LLVM

; RUN: llc -mtriple=x86_64-linux -fast-isel -show-mc-encoding < %s | FileCheck %s
; CHECK-LABEL: f:
; CHECK: addl $-2, %eax # encoding: [0x83,0xc0,0xfe]
define i32 @f(i32* %y) {
%x = load i32, i32* %y
%dec = add i32 %x, -2
ret i32 %dec
}