llvm-project/llvm/test/CodeGen/X86/fast-isel-sext.ll

; 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
}
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. llvm-svn: 234249 2015-04-07 06:29:07 +08:00			`; 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`
			`}`