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llvm-mirror/test/CodeGen/X86/pr30290.ll
Jeremy Morse cee4caaf3e [X86] Mark all byval parameters as aliased
This is a fix for PR30290: by marking all byval stack slots as being aliased,
the instruction scheduler is more conservative about rescheduling memory
accesses to such stack slots as an LLVM Value* might alias it. This fixes
errors such as in the patched test case, where reads and writes to a data
structure are illegally mixed.

This could be fixed better in the future with better analysis for the
instruction scheduler to know what Values alias what stack slots.

Differential Revision: https://reviews.llvm.org/D45022

llvm-svn: 331749
2018-05-08 09:18:01 +00:00

41 lines
1.7 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc -mcpu=btver2 %s -o - | FileCheck %s
; Test desc: two functions (foo, bar) with byval arguments, should not have
; reads/writes from/to byval storage re-ordered.
; When broken, five "1" constants are written into the byval %struct.face,
; but the subsequent byval read of that struct (call to bar) gets re-ordered
; before those writes, illegally.
source_filename = "test.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-linux-gnu"
%struct.face = type { [7 x i32] }
; Function Attrs: noinline nounwind uwtable
declare void @bar(%struct.face* byval nocapture readonly align 8);
; Function Attrs: noinline nounwind uwtable
define void @foo(%struct.face* byval nocapture align 8) local_unnamed_addr {
; CHECK-LABEL: foo:
; CHECK: # %bb.0:
; CHECK-NEXT: subq $40, %rsp
; CHECK-NEXT: .cfi_def_cfa_offset 48
; CHECK-NEXT: vmovaps {{.*#+}} xmm0 = [1,1,1,1]
; CHECK-NEXT: vmovaps %xmm0, {{[0-9]+}}(%rsp)
; CHECK-NEXT: movl $1, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovups {{[0-9]+}}(%rsp), %xmm0
; CHECK-NEXT: vmovups %xmm0, {{[0-9]+}}(%rsp)
; CHECK-NEXT: vmovaps {{[0-9]+}}(%rsp), %xmm0
; CHECK-NEXT: vmovups %xmm0, (%rsp)
; CHECK-NEXT: callq bar
; CHECK-NEXT: addq $40, %rsp
; CHECK-NEXT: .cfi_def_cfa_offset 8
; CHECK-NEXT: retq
%2 = bitcast %struct.face* %0 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %2, align 8
%3 = getelementptr inbounds %struct.face, %struct.face* %0, i64 0, i32 0, i64 4
store i32 1, i32* %3, align 8
call void @bar(%struct.face* byval nonnull align 8 %0)
ret void
}