blob: 50e736ac68d29ee83eb0b6feba570c0faf24b16e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
; RUN: llc < %s | FileCheck %s
; Check that the shr(shl X, 56), 48) is not mistakenly turned into
; a shr (X, -8) that gets subsequently "optimized away" as undef
; PR4254
; after fixing PR24373
; shlq $56, %rdi
; sarq $48, %rdi
; folds into
; movsbq %dil, %rax
; shlq $8, %rax
; which is better for x86
target 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"
target triple = "x86_64-unknown-linux-gnu"
define i64 @foo(i64 %b) nounwind readnone {
; CHECK-LABEL: foo:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: movsbq %dil, %rax
; CHECK-NEXT: shlq $8, %rax
; CHECK-NEXT: incq %rax
; CHECK-NEXT: retq
entry:
%shl = shl i64 %b, 56 ; <i64> [#uses=1]
%shr = ashr i64 %shl, 48 ; <i64> [#uses=1]
%add5 = or i64 %shr, 1 ; <i64> [#uses=1]
ret i64 %add5
}
|
