view test/CodeGen/X86/sext-load.ll @ 33:e4204d083e25

LLVM 3.5
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 14:32:10 +0900
parents 95c75e76d11b
children afa8332a0e37
line wrap: on
line source

; RUN: llc < %s -march=x86 | FileCheck %s

; When doing sign extension, use the sext-load lowering to take advantage of
; x86's sign extension during loads.
;
; CHECK-LABEL: test1:
; CHECK:      movsbl {{.*}}, %eax
; CHECK-NEXT: ret
define i32 @test1(i32 %X) nounwind  {
entry:
	%tmp12 = trunc i32 %X to i8		; <i8> [#uses=1]
	%tmp123 = sext i8 %tmp12 to i32		; <i32> [#uses=1]
	ret i32 %tmp123
}

; When using a sextload representation, ensure that the sign extension is
; preserved even when removing shifted-out low bits.
;
; CHECK-LABEL: test2:
; CHECK:      movswl {{.*}}, %eax
; CHECK-NEXT: ret
define i32 @test2({i16, [6 x i8]}* %this) {
entry:
  %b48 = getelementptr inbounds { i16, [6 x i8] }* %this, i32 0, i32 1
  %cast = bitcast [6 x i8]* %b48 to i48*
  %bf.load = load i48* %cast, align 2
  %bf.ashr = ashr i48 %bf.load, 32
  %bf.cast = trunc i48 %bf.ashr to i32
  ret i32 %bf.cast
}