| ; 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 |
| } |
