llvm-6502/pr21099.ll at 671944ff8fc9ca8206964d51586a2f541a441262 - llvm-6502 - Applefritter: Git

6502/llvm-6502

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Robin Morisset 28127ffb51 [X86] Fix a bug with fetch_add(INT32_MIN)

Summary:
Fix pr21099

The pseudocode of what we were doing (spread through two functions) was:
if (operand.doesNotFitIn32Bits())
  Opc.initializeWithFoo();
if (operand < 0)
  operand = -operand;
if (operand.doesFitIn8Bits())
  Opc.initializeWithBar();
else if (operand.doesFitIn32Bits())
  Opc.initializeWithBlah();
doStuff(Opc);

So for operand == INT32_MIN, Opc was never initialized because the operand changes
from fitting in 32 bits to not fitting, causing the various bugs/error messages
noted by pr21099.

This patch adds an extra test at the beginning for this case, and an
llvm_unreachable to have better error message if the operand ends up
not fitting in 32-bits at the end.

Test Plan: new test + make check

Reviewers: jfb

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5655

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219257 91177308-0d34-0410-b5e6-96231b3b80d8

2014-10-07 23:53:57 +00:00

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 ; RUN: llc < %s -O2 -march=x86-64 -verify-machineinstrs | FileCheck %s
 define void @pr21099(i64* %p) {
 ; CHECK-LABEL: pr21099
 ; CHECK: lock
 ; CHECK-NEXT: addq $-2147483648
 ; This number is INT32_MIN: 0x80000000UL
   %1 = atomicrmw add i64* %p, i64 -2147483648 seq_cst
   ret void
 }