1; RUN: llc < %s | FileCheck %s
2
3; Check that the shr(shl X, 56), 48) is not mistakenly turned into
4; a shr (X, -8) that gets subsequently "optimized away" as undef
5; PR4254
6
7; after fixing PR24373
8; shlq $56, %rdi
9; sarq $48, %rdi
10; folds into
11; movsbq %dil, %rax
12; shlq $8, %rax
13; which is better for x86
14
15target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
16target triple = "x86_64-unknown-linux-gnu"
17
18define i64 @foo(i64 %b) nounwind readnone {
19entry:
20; CHECK-LABEL: foo:
21; CHECK: movsbq %dil, %rax
22; CHECK: shlq $8, %rax
23; CHECK: orq $1, %rax
24	%shl = shl i64 %b, 56		; <i64> [#uses=1]
25	%shr = ashr i64 %shl, 48		; <i64> [#uses=1]
26	%add5 = or i64 %shr, 1		; <i64> [#uses=1]
27	ret i64 %add5
28}
29