File: sext-load.ll

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llvm-toolchain-13 1%3A13.0.1-11
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; RUN: llc < %s -mtriple=i686-- | 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] }, { i16, [6 x i8] }* %this, i32 0, i32 1
  %cast = bitcast [6 x i8]* %b48 to i48*
  %bf.load = load i48, i48* %cast, align 2
  %bf.ashr = ashr i48 %bf.load, 32
  %bf.cast = trunc i48 %bf.ashr to i32
  ret i32 %bf.cast
}