Commit Graph

25 Commits

Author SHA1 Message Date
Benjamin Kramer f4c2025357 [CodeGen] Reduce visibility of implementation details
NFC.

llvm-svn: 241164
2015-07-01 14:47:39 +00:00
Alexander Kornienko f00654e31b Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
2015-06-23 09:49:53 +00:00
Alexander Kornienko 70bc5f1398 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
Benjamin Kramer a7c40ef022 Canonicalize header guards into a common format.
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)

Changes made by clang-tidy with minor tweaks.

llvm-svn: 215558
2014-08-13 16:26:38 +00:00
Akira Hatanaka bbd33f6766 [Branch probability] Recompute branch weights of tail-merged basic blocks.
BranchFolderPass was not correctly setting the basic block branch weights when
tail-merging created or merged blocks. This patch recomutes the weights of
tail-merged blocks using the following formula:

branch_weight(merged block to successor j) =
sum(block_frequency(bb) * branch_probability(bb -> j))

bb is a block that is in the set of merged blocks.

<rdar://problem/16256423>

llvm-svn: 215135
2014-08-07 19:30:13 +00:00
Benjamin Kramer 079b96e6f7 Revert "Give internal classes hidden visibility."
It works with clang, but GCC has different rules so we can't make all of those
hidden. This reverts commit r190534.

llvm-svn: 190536
2013-09-11 18:05:11 +00:00
Benjamin Kramer 6a44af3629 Give internal classes hidden visibility.
Worth 100k on a linux/x86_64 Release+Asserts clang.

llvm-svn: 190534
2013-09-11 17:42:27 +00:00
Michael Gottesman 1649a877e1 [branchfolding] Fix typo in C++ editor declaration.
llvm-svn: 188201
2013-08-12 20:49:27 +00:00
Andrew Trick 97a1d7c475 Fix tail merging to assign the (more) correct BasicBlock when splitting.
This makes it possible to write unit tests that are less susceptible
to minor code motion, particularly copy placement. block-placement.ll
covers this case with -pre-RA-sched=source which will soon be
default. One incorrectly named block is already fixed, but without
this fix, enabling new coalescing and scheduling would cause more
failures.

llvm-svn: 184680
2013-06-24 01:55:01 +00:00
Eli Friedman bf007364bf When tail-merging multiple blocks, make sure to correctly update the live-in list on the merged block to correctly account for the live-outs of all the predecessors. They might not be the same in all cases (the testcase I have involves a PHI node where one of the operands is an IMPLICIT_DEF).
Unfortunately, the testcase I have is large and confidential, so I don't have a test to commit at the moment; I'll see if I can come up with something smaller where this issue reproduces.

<rdar://problem/9716278>

llvm-svn: 134565
2011-07-06 23:41:48 +00:00
Rafael Espindola 3aeaf9e4c1 Add 132986 back, but avoid non-determinism if a bb address gets reused.
llvm-svn: 132995
2011-06-14 15:31:54 +00:00
Rafael Espindola 06ba7a68de revert 132986 to see if the bots go green.
llvm-svn: 132988
2011-06-14 12:48:26 +00:00
Rafael Espindola da24f2f8e1 Make the threshold used by branch folding softer. Before we would get a
sharp all or nothing transition when one extra predecessor was added. Now
we still test first ones for merging.

llvm-svn: 132974
2011-06-14 04:41:17 +00:00
Evan Cheng cfdf33904b Re-commit 131172 with fix. MachineInstr identity checks should check dead
markers. In some cases a register def is dead on one path, but not on
another.

This is passing Clang self-hosting.

llvm-svn: 131214
2011-05-12 00:56:58 +00:00
Rafael Espindola 2a09d65979 Revert 131172 as it is causing clang to miscompile itself. I will try
to provide a reduced testcase.

llvm-svn: 131176
2011-05-11 03:27:17 +00:00
Evan Cheng 05fc35e275 Add a late optimization to BranchFolding that hoist common instruction sequences
at the start of basic blocks to their common predecessor. It's actually quite
common (e.g. about 50 times in JM/lencod) and has shown to be a nice code size
benefit. e.g.

        pushq   %rax
        testl   %edi, %edi
        jne     LBB0_2
## BB#1:
        xorb    %al, %al
        popq    %rdx
        ret
LBB0_2:
        xorb    %al, %al
        callq   _foo
        popq    %rdx
        ret

=>

        pushq   %rax
        xorb    %al, %al
        testl   %edi, %edi
        je      LBB0_2
## BB#1:
        callq   _foo
LBB0_2:
        popq    %rdx
        ret

rdar://9145558

llvm-svn: 131172
2011-05-11 01:03:01 +00:00
Evan Cheng 37bb617f8a Tail merging pass shall not break up IT blocks. rdar://8115404
llvm-svn: 106517
2010-06-22 01:18:16 +00:00
Bob Wilson 2d4ff12da9 Split tail duplication into a separate pass. This is needed to avoid
running tail duplication when doing branch folding for if-conversion, and
we also want to be able to run tail duplication earlier to fix some
reg alloc problems.  Move the CanFallThrough function from BranchFolding
to MachineBasicBlock so that it can be shared by TailDuplication.

llvm-svn: 89904
2009-11-26 00:32:21 +00:00
Bob Wilson bd22f1965d Perform tail duplication only once, after tail merging is complete.
It was too difficult to keep the heuristics for merging and duplication
consistent.

llvm-svn: 89105
2009-11-17 17:06:18 +00:00
Dan Gohman a9b40a6eb4 Make the BranchFolderPass class local to BranchFolding.cpp.
llvm-svn: 86928
2009-11-12 01:59:26 +00:00
Dan Gohman 02b155427e Promote MergePotentialsElt and SameTailElt to be regular classes
instead of typedefs for std::pair. This simplifies the type of
SameTails, which previously was std::vector<std::pair<std::vector<std::pair<unsigned, MachineBasicBlock *> >::iterator, MachineBasicBlock::iterator>

llvm-svn: 86885
2009-11-11 21:57:02 +00:00
Dan Gohman 34eeb4e983 Check in the changes to this file too.
llvm-svn: 86873
2009-11-11 19:49:34 +00:00
Bob Wilson 97b9312663 Revert r85346 change to control tail merging by CodeGenOpt::Level.
I'm going to redo this using the OptimizeForSize function attribute.

llvm-svn: 85426
2009-10-28 20:46:46 +00:00
Bob Wilson 9693f9d465 Record CodeGen optimization level in the BranchFolding pass so that we can
use it to control tail merging when there is a tradeoff between performance
and code size.  When there is only 1 instruction in the common tail, we have
been merging.  That can be good for code size but is a definite loss for
performance.  Now we will avoid tail merging in that case when the
optimization level is "Aggressive", i.e., "-O3".  Radar 7338114.

Since the IfConversion pass invokes BranchFolding, it too needs to know
the optimization level.  Note that I removed the RegisterPass instantiation
for IfConversion because it required a default constructor.  If someone
wants to keep that for some reason, we can add a default constructor with
a hard-wired optimization level.

llvm-svn: 85346
2009-10-27 23:49:38 +00:00
Evan Cheng 3d2fce01aa Run branch folding if if-converter make some transformations.
llvm-svn: 80994
2009-09-04 07:47:40 +00:00