From e33a8b8c2f003b703b0af32effd8ef25477c2165 Mon Sep 17 00:00:00 2001
From: Michael Gottesman <mgottesman@apple.com>
Date: Thu, 3 Jan 2013 08:18:30 +0000
Subject: [PATCH] Revert "Mark DIV/IDIV instructions hasSideEffects=1 because
 they can trap when dividing by 0. This is needed to keep early if conversion
 from moving them across basic blocks."

This reverts commit r171461 since it breaks the following tests:

Clang :: Analysis/outofbound-notwork.c
Clang :: Analysis/string-fail.c
Clang :: CXX/basic/basic.lookup/basic.lookup.qual/p6-0x.cpp
Clang :: CXX/basic/basic.lookup/basic.lookup.unqual/p15.cpp
Clang :: CXX/dcl.dcl/dcl.spec/dcl.fct.spec/p4.cpp
Clang :: CXX/dcl.dcl/dcl.spec/dcl.stc/p10.cpp
Clang :: CXX/temp/temp.param/p14.cpp
Clang :: CXX/temp/temp.res/temp.dep.res/temp.point/p1.cpp
Clang :: CodeGen/2009-02-13-zerosize-union-field-ppc.c
Clang :: CodeGen/blocks-2.c
Clang :: CodeGen/libcalls-d.c
Clang :: CodeGen/libcalls-ld.c
Clang :: CodeGenCXX/conversion-function.cpp
Clang :: CodeGenCXX/debug-info-limit-type.cpp
Clang :: CodeGenCXX/inheriting-constructor.cpp
Clang :: FixIt/fixit-errors.c
Clang :: FixIt/fixit-pmem.cpp
Clang :: Modules/namespaces.cpp
Clang :: PCH/changed-files.c
Clang :: PCH/pr4489.c
Clang :: PCH/source-manager-stack.c
Clang :: Parser/cxx-ambig-decl-expr-xfail.cpp
Clang :: SemaCXX/switch-implicit-fallthrough-cxx98.cpp
Clang :: SemaTemplate/instantiate-function-1.mm

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171466 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86InstrArithmetic.td |  2 +-
 test/CodeGen/X86/early-ifcvt.ll      | 32 ----------------------------
 2 files changed, 1 insertion(+), 33 deletions(-)

diff --git a/lib/Target/X86/X86InstrArithmetic.td b/lib/Target/X86/X86InstrArithmetic.td
index 3540fc31257..d56763ea9d2 100644
--- a/lib/Target/X86/X86InstrArithmetic.td
+++ b/lib/Target/X86/X86InstrArithmetic.td
@@ -266,7 +266,7 @@ def IMUL64rmi8 : RIi8<0x6B, MRMSrcMem,                      // GR64 = [mem64]*I8
 
 
 // unsigned division/remainder
-let hasSideEffects = 1 in { // so that we don't speculatively execute
+let hasSideEffects = 0 in {
 let Defs = [AL,EFLAGS,AX], Uses = [AX] in
 def DIV8r  : I<0xF6, MRM6r, (outs),  (ins GR8:$src),    // AX/r8 = AL,AH
                "div{b}\t$src", [], IIC_DIV8_REG>;
diff --git a/test/CodeGen/X86/early-ifcvt.ll b/test/CodeGen/X86/early-ifcvt.ll
index b3a20c3ee0b..2e1852d3e3a 100644
--- a/test/CodeGen/X86/early-ifcvt.ll
+++ b/test/CodeGen/X86/early-ifcvt.ll
@@ -142,35 +142,3 @@ save_state_and_return:
 }
 
 declare void @BZ2_bz__AssertH__fail()
-
-
-; Make sure we don't speculate on div/idiv instructions
-; CHECK: test_idiv
-; CHECK-NOT: cmov
-define i32 @test_idiv(i32 %a, i32 %b) nounwind uwtable readnone ssp {
-  %1 = icmp eq i32 %b, 0
-  br i1 %1, label %4, label %2
-
-; <label>:2                                       ; preds = %0
-  %3 = sdiv i32 %a, %b
-  br label %4
-
-; <label>:4                                       ; preds = %0, %2
-  %5 = phi i32 [ %3, %2 ], [ %a, %0 ]
-  ret i32 %5
-}
-
-; CHECK: test_div
-; CHECK-NOT: cmov
-define i32 @test_div(i32 %a, i32 %b) nounwind uwtable readnone ssp {
-  %1 = icmp eq i32 %b, 0
-  br i1 %1, label %4, label %2
-
-; <label>:2                                       ; preds = %0
-  %3 = udiv i32 %a, %b
-  br label %4
-
-; <label>:4                                       ; preds = %0, %2
-  %5 = phi i32 [ %3, %2 ], [ %a, %0 ]
-  ret i32 %5
-}