| ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py |
| ; RUN: llc -O1 -mtriple i686-unknown-linux-gnu -o - %s | FileCheck %s |
| |
| @foo = global i16 0, align 1 |
| @aliasFoo = alias i16, i16 * @foo |
| @bar = global i16 0, align 1 |
| |
| ; This used to miscompile due to not realizing that the store to @aliasFoo |
| ; clobbered @foo (see PR51878). |
| ; |
| ; With some improvements to codegen it should be possible to detect that @foo |
| ; and @aliasFoo are aliases, and that @aliasFoo isn't aliasing with @bar. So |
| ; ideally we would end up with three movw instructions here. Running opt |
| ; before llc on this test case would take care of that, but llc is not smart |
| ; enough to deduce that itself yet. |
| define i16 @main() { |
| ; CHECK-LABEL: main: |
| ; CHECK: # %bb.0: # %entry |
| ; CHECK-NEXT: movw $1, foo |
| ; CHECK-NEXT: movw $2, bar |
| ; CHECK-NEXT: movw $4, aliasFoo |
| ; CHECK-NEXT: movzwl foo, %eax |
| ; CHECK-NEXT: addw bar, %ax |
| ; CHECK-NEXT: retl |
| entry: |
| store i16 1, i16 * @foo |
| store i16 2, i16 * @bar |
| store i16 4, i16 * @aliasFoo |
| %foo = load i16, i16 * @foo |
| %bar = load i16, i16 * @bar |
| %res = add i16 %foo, %bar |
| ret i16 %res |
| } |
