[llvm] r366760 - [Statepoints] Add a test which shows a miscompile with no-realign-stacks

[Philip Reames via llvm-commits]

Author: reames
Date: Mon Jul 22 16:08:56 2019
New Revision: 366760

URL: http://llvm.org/viewvc/llvm-project?rev=366760&view=rev
Log:
[Statepoints] Add a test which shows a miscompile with no-realign-stacks


Added:
    llvm/trunk/test/CodeGen/X86/statepoint-no-realign-stack.ll

Added: llvm/trunk/test/CodeGen/X86/statepoint-no-realign-stack.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/statepoint-no-realign-stack.ll?rev=366760&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/statepoint-no-realign-stack.ll (added)
+++ llvm/trunk/test/CodeGen/X86/statepoint-no-realign-stack.ll Mon Jul 22 16:08:56 2019
@@ -0,0 +1,55 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -verify-machineinstrs -mcpu=skylake < %s | FileCheck %s
+
+target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-linux-gnu"
+
+; Shows a case where we spill a 32 byte value onto a stack which is only
+; 16 byte aligned.  With stack realignment, we can use an aligned spill slot
+; (if we think it's profitable), but without realignment, using a stack
+; slot which is 32 byte aligned or a store which expects 32 byte alignment
+; is incorrect.
+
+declare void @foo()
+define void @can_realign(<8 x i32>* %p) {
+; CHECK-LABEL: can_realign:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pushq %rbp
+; CHECK-NEXT:    .cfi_def_cfa_offset 16
+; CHECK-NEXT:    .cfi_offset %rbp, -16
+; CHECK-NEXT:    movq %rsp, %rbp
+; CHECK-NEXT:    .cfi_def_cfa_register %rbp
+; CHECK-NEXT:    andq $-32, %rsp
+; CHECK-NEXT:    subq $64, %rsp
+; CHECK-NEXT:    vmovaps (%rdi), %ymm0
+; CHECK-NEXT:    vmovaps %ymm0, (%rsp)
+; CHECK-NEXT:    vzeroupper
+; CHECK-NEXT:    callq foo
+; CHECK-NEXT:  .Ltmp0:
+; CHECK-NEXT:    movq %rbp, %rsp
+; CHECK-NEXT:    popq %rbp
+; CHECK-NEXT:    .cfi_def_cfa %rsp, 8
+; CHECK-NEXT:    retq
+  %val = load <8 x i32>, <8 x i32>* %p, align 32
+  call void @foo() ["deopt" (<8 x i32> %val)]
+  ret void
+}
+
+; TODO: currently shows incorrect codegen, FIXME
+define void @no_realign(<8 x i32>* %p) "no-realign-stack" {
+; CHECK-LABEL: no_realign:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    subq $40, %rsp
+; CHECK-NEXT:    .cfi_def_cfa_offset 48
+; CHECK-NEXT:    vmovaps (%rdi), %ymm0
+; CHECK-NEXT:    vmovaps %ymm0, (%rsp)
+; CHECK-NEXT:    vzeroupper
+; CHECK-NEXT:    callq foo
+; CHECK-NEXT:  .Ltmp1:
+; CHECK-NEXT:    addq $40, %rsp
+; CHECK-NEXT:    .cfi_def_cfa_offset 8
+; CHECK-NEXT:    retq
+  %val = load <8 x i32>, <8 x i32>* %p, align 32
+  call void @foo() ["deopt" (<8 x i32> %val)]
+  ret void
+}