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 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" 8 target triple = "x86_64-unknown-linux-gnu" 9 10 define i64 @foo(i64 %b) nounwind readnone { 11 entry: 12 ; CHECK: foo: 13 ; CHECK: shlq $56, %rdi 14 ; CHECK: sarq $48, %rdi 15 ; CHECK: leaq 1(%rdi), %rax 16 %shl = shl i64 %b, 56 ; <i64> [#uses=1] 17 %shr = ashr i64 %shl, 48 ; <i64> [#uses=1] 18 %add5 = or i64 %shr, 1 ; <i64> [#uses=1] 19 ret i64 %add5 20 } 21
