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 15 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" 16 target triple = "x86_64-unknown-linux-gnu" 17 18 define i64 @foo(i64 %b) nounwind readnone { 19 entry: 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
