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Florian Hahn c74808b914 [PredicateInfo] Replace pointer comparisons with deterministic compares. 
Currently there are a few pointer comparisons in ValueDFS_Compare, which
can cause non-deterministic ordering when materializing values. There
are 2 cases this patch fixes:

1. Order defs before uses used to compare pointers, which guarantees
   defs before uses, but causes non-deterministic ordering between 2
   uses or 2 defs, depending on the allocation order. By converting the
   pointers to booleans, we can circumvent that problem.

2. comparePHIRelated was comparing the basic block pointers of edges,
   which also results in a non-deterministic order and is also not
   really meaningful for ordering. By ordering by their destination DFS
   numbers we guarantee a deterministic order.

For the example below, we can end up with 2 different uselist orderings,
when running `opt -mem2reg -ipsccp` hundreds of times. Because the
non-determinism is caused by allocation ordering, we cannot reproduce it
with ipsccp alone.

    declare i32 @hoge() local_unnamed_addr #0

    define dso_local i32 @ham(i8* %arg, i8* %arg1) #0 {
    bb:
      %tmp = alloca i32
      %tmp2 = alloca i32, align 4
      br label %bb19

    bb4:                                              ; preds = %bb20
      br label %bb6

    bb6:                                              ; preds = %bb4
      %tmp7 = call i32 @hoge()
      store i32 %tmp7, i32* %tmp
      %tmp8 = load i32, i32* %tmp
      %tmp9 = icmp eq i32 %tmp8, 912730082
      %tmp10 = load i32, i32* %tmp
      br i1 %tmp9, label %bb11, label %bb16

    bb11:                                             ; preds = %bb6
      unreachable

    bb13:                                             ; preds = %bb20
      br label %bb14

    bb14:                                             ; preds = %bb13
      %tmp15 = load i32, i32* %tmp
      br label %bb16

    bb16:                                             ; preds = %bb14, %bb6
      %tmp17 = phi i32 [ %tmp10, %bb6 ], [ 0, %bb14 ]
      br label %bb19

    bb18:                                             ; preds = %bb20
      unreachable

    bb19:                                             ; preds = %bb16, %bb
      br label %bb20

    bb20:                                             ; preds = %bb19
      indirectbr i8* null, [label %bb4, label %bb13, label %bb18]
    }

Reviewers: davide, efriedma

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D64866

llvm-svn: 367049
 		2019-07-25 20:48:13 +00:00
clang CodeGen: ensure placeholder instruction for cleanup is created 2019-07-25 17:59:29 +00:00
clang-tools-extra [clang-doc] Fix html entities in rendered text 2019-07-25 20:14:45 +00:00
compiler-rt [sanitizer_common] Allow customization of StartSymbolizerSubprocess 2019-07-25 00:19:02 +00:00
debuginfo-tests Make nrvo-string test more robust. 2019-06-27 20:38:37 +00:00
libclc travis: Add LLVM-8 build 2019-03-27 21:28:31 +00:00
libcxx [NFC][libcxx] Add comments about making mutex/condition_variable trivial on Apple platforms 2019-07-25 20:29:20 +00:00
libcxxabi [runtimes] Don't depend on libpthread on Android 2019-07-22 20:41:03 +00:00
libunwind [runtimes] Don't depend on libpthread on Android 2019-07-22 20:41:03 +00:00
lld [ELF][MIPS] Improve tests 2019-07-25 07:12:23 +00:00
lldb [lldb] [Process/NetBSD] Report stopped process on SIGSTOP 2019-07-25 20:27:40 +00:00
llgo IR: Support parsing numeric block ids, and emit them in textual output. 2019-03-22 18:27:13 +00:00
llvm [PredicateInfo] Replace pointer comparisons with deterministic compares. 2019-07-25 20:48:13 +00:00
openmp [OpenMP] Fix build of stubs library, NFC. 2019-07-25 17:51:24 +00:00
parallel-libs Fix typos throughout the license files that somehow I and my reviewers 2019-01-21 09:52:34 +00:00
polly [Polly] Clang complains about missing virtual destructor 2019-07-22 15:34:27 +00:00
pstl Revert "[libc++] Integrate the PSTL into libc++" 2019-07-19 18:52:46 +00:00
.arcconfig Update monorepo .arcconfig with new project callsign. 2019-01-31 14:34:59 +00:00
.clang-format Add .clang-tidy and .clang-format files to the toplevel of the 2019-01-29 16:43:16 +00:00
.clang-tidy Disable tidy checks with too many hits 2019-02-01 11:20:13 +00:00
.gitignore Add a reduced copy of the llvm .gitignore 2019-04-09 00:52:49 +00:00
README.md
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README.md

The LLVM Compiler Infrastructure

This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.