Commit Graph

39 Commits

Author SHA1 Message Date
Craig Topper df7454f94b Revert "[ValueTracking] Teach computeKnownBits for PHI nodes to compute sign bit for a recurrence with a NSW addition."
This is breaking an optimizaton remark test in clang. I've identified a couple fixes for that, but want to understand it better before I commit to anything.

llvm-svn: 274102
2016-06-29 04:57:00 +00:00
Craig Topper 2cc199baff [ValueTracking] Teach computeKnownBits for PHI nodes to compute sign bit for a recurrence with a NSW addition.
If a operation for a recurrence is an addition with no signed wrap and both input sign bits are 0, then the result sign bit must also be 0. Similar for the negative case.

I found this deficiency while playing around with a loop in the x86 backend that contained a signed division that could be optimized into an unsigned division if we could prove both inputs were positive. One of them being the loop induction variable. With this patch we can perform the conversion for this case. One of the test cases here is a contrived variation of the loop I was looking at.

Differential revision: http://reviews.llvm.org/D21493

llvm-svn: 274098
2016-06-29 03:46:47 +00:00
Jun Bum Lim 339e9723c1 [InstCombine] Simplify a known nonzero incoming value of PHI
Summary:
When a PHI is used only to be compared with zero, it is possible to replace an
incoming value with any non-zero constant if the incoming value can be proved as
a known nonzero value. For example, in below code, we can replace the incoming value %v with
any non-zero constant based on the fact that the PHI is only used to be compared with zero
and %v is a known non-zero value:
  %v = select %cond, 1, 2
  %p = phi [%v, BB] ...
  %c = icmp eq, %p, 0

Reviewers: mcrosier, jmolloy, sanjoy

Subscribers: hfinkel, mcrosier, majnemer, llvm-commits, haicheng, bmakam, mssimpso, gberry

Differential Revision: http://reviews.llvm.org/D16240

llvm-svn: 260530
2016-02-11 15:50:07 +00:00
Jun Bum Lim ca832660ae [ValueTracking] Improve isKnownNonZero for PHI of non-zero constants
It is clear that a PHI is a non-zero if all incoming values are non-zero constants.

llvm-svn: 259370
2016-02-01 17:03:07 +00:00
Sanjay Patel 9533407566 [InstCombine] fold zexts and constants into a phi (PR24766)
This is one step towards solving PR24766:
https://llvm.org/bugs/show_bug.cgi?id=24766

We were not producing the same IR for these two C functions because the store
to the temp bool causes extra zexts:

#include <stdbool.h>

bool switchy(char x1, char x2, char condition) {
   bool conditionMet = false;
   switch (condition) {
   case 0: conditionMet = (x1 == x2); break;
   case 1: conditionMet = (x1 <= x2); break;
   }
   return conditionMet;
}

bool switchy2(char x1, char x2, char condition) {
   switch (condition) {
   case 0: return (x1 == x2);
   case 1: return (x1 <= x2);
   }
  return false;
}

As noted in the code comments, this test case manages to avoid the more general existing
phi optimizations where there are only 2 phi inputs or where there are no constant phi 
args mixed in with the casts ops. It seems like a corner case, but if we don't catch it, 
then I don't think we can get SimplifyCFG to further optimize towards the canonical form
for this function shown in the bug report.

Differential Revision: http://reviews.llvm.org/D12866

llvm-svn: 248689
2015-09-27 20:34:31 +00:00
David Majnemer 8ed559ad22 Revert "[InstCombinePHI] Partial simplification of identity operations."
This reverts commit r244887, it caused PR24470.

llvm-svn: 245194
2015-08-17 03:11:26 +00:00
Charlie Turner 6153698f26 [InstCombinePHI] Partial simplification of identity operations.
Consider this code:

BB:
  %i = phi i32 [ 0, %if.then ], [ %c, %if.else ]
  %add = add nsw i32 %i, %b
  ...

In this common case the add can be moved to the %if.else basic block, because
adding zero is an identity operation. If we go though %if.then branch it's
always a win, because add is not executed; if not, the number of instructions
stays the same.

This pattern applies also to other instructions like sub, shl, shr, ashr | 0,
mul, sdiv, div | 1.

Patch by Jakub Kuderski!

llvm-svn: 244887
2015-08-13 12:38:58 +00:00
David Blaikie a79ac14fa6 [opaque pointer type] Add textual IR support for explicit type parameter to load instruction
Essentially the same as the GEP change in r230786.

A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)

import fileinput
import sys
import re

pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")

for line in sys.stdin:
  sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7649

llvm-svn: 230794
2015-02-27 21:17:42 +00:00
David Blaikie 79e6c74981 [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction
One of several parallel first steps to remove the target type of pointers,
replacing them with a single opaque pointer type.

This adds an explicit type parameter to the gep instruction so that when the
first parameter becomes an opaque pointer type, the type to gep through is
still available to the instructions.

* This doesn't modify gep operators, only instructions (operators will be
  handled separately)

* Textual IR changes only. Bitcode (including upgrade) and changing the
  in-memory representation will be in separate changes.

* geps of vectors are transformed as:
    getelementptr <4 x float*> %x, ...
  ->getelementptr float, <4 x float*> %x, ...
  Then, once the opaque pointer type is introduced, this will ultimately look
  like:
    getelementptr float, <4 x ptr> %x
  with the unambiguous interpretation that it is a vector of pointers to float.

* address spaces remain on the pointer, not the type:
    getelementptr float addrspace(1)* %x
  ->getelementptr float, float addrspace(1)* %x
  Then, eventually:
    getelementptr float, ptr addrspace(1) %x

Importantly, the massive amount of test case churn has been automated by
same crappy python code. I had to manually update a few test cases that
wouldn't fit the script's model (r228970,r229196,r229197,r229198). The
python script just massages stdin and writes the result to stdout, I
then wrapped that in a shell script to handle replacing files, then
using the usual find+xargs to migrate all the files.

update.py:
import fileinput
import sys
import re

ibrep = re.compile(r"(^.*?[^%\w]getelementptr inbounds )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))")
normrep = re.compile(       r"(^.*?[^%\w]getelementptr )(((?:<\d* x )?)(.*?)(| addrspace\(\d\)) *\*(|>)(?:$| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$))")

def conv(match, line):
  if not match:
    return line
  line = match.groups()[0]
  if len(match.groups()[5]) == 0:
    line += match.groups()[2]
  line += match.groups()[3]
  line += ", "
  line += match.groups()[1]
  line += "\n"
  return line

for line in sys.stdin:
  if line.find("getelementptr ") == line.find("getelementptr inbounds"):
    if line.find("getelementptr inbounds") != line.find("getelementptr inbounds ("):
      line = conv(re.match(ibrep, line), line)
  elif line.find("getelementptr ") != line.find("getelementptr ("):
    line = conv(re.match(normrep, line), line)
  sys.stdout.write(line)

apply.sh:
for name in "$@"
do
  python3 `dirname "$0"`/update.py < "$name" > "$name.tmp" && mv "$name.tmp" "$name"
  rm -f "$name.tmp"
done

The actual commands:
From llvm/src:
find test/ -name *.ll | xargs ./apply.sh
From llvm/src/tools/clang:
find test/ -name *.mm -o -name *.m -o -name *.cpp -o -name *.c | xargs -I '{}' ../../apply.sh "{}"
From llvm/src/tools/polly:
find test/ -name *.ll | xargs ./apply.sh

After that, check-all (with llvm, clang, clang-tools-extra, lld,
compiler-rt, and polly all checked out).

The extra 'rm' in the apply.sh script is due to a few files in clang's test
suite using interesting unicode stuff that my python script was throwing
exceptions on. None of those files needed to be migrated, so it seemed
sufficient to ignore those cases.

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7636

llvm-svn: 230786
2015-02-27 19:29:02 +00:00
Stephen Lin c1c7a1309c Update Transforms tests to use CHECK-LABEL for easier debugging. No functionality change.
This update was done with the following bash script:

  find test/Transforms -name "*.ll" | \
  while read NAME; do
    echo "$NAME"
    if ! grep -q "^; *RUN: *llc" $NAME; then
      TEMP=`mktemp -t temp`
      cp $NAME $TEMP
      sed -n "s/^define [^@]*@\([A-Za-z0-9_]*\)(.*$/\1/p" < $NAME | \
      while read FUNC; do
        sed -i '' "s/;\(.*\)\([A-Za-z0-9_]*\):\( *\)@$FUNC\([( ]*\)\$/;\1\2-LABEL:\3@$FUNC(/g" $TEMP
      done
      mv $TEMP $NAME
    fi
  done

llvm-svn: 186268
2013-07-14 01:42:54 +00:00
Dan Gohman 1ccecdb2fd Reapply r155682, making constant folding more consistent, with a fix to work
properly with how the code handles all-undef PHI nodes.

llvm-svn: 155721
2012-04-27 17:50:22 +00:00
Chris Lattner b1ed91f397 Land the long talked about "type system rewrite" patch. This
patch brings numerous advantages to LLVM.  One way to look at it
is through diffstat:
 109 files changed, 3005 insertions(+), 5906 deletions(-)

Removing almost 3K lines of code is a good thing.  Other advantages
include:

1. Value::getType() is a simple load that can be CSE'd, not a mutating
   union-find operation.
2. Types a uniqued and never move once created, defining away PATypeHolder.
3. Structs can be "named" now, and their name is part of the identity that
   uniques them.  This means that the compiler doesn't merge them structurally
   which makes the IR much less confusing.
4. Now that there is no way to get a cycle in a type graph without a named
   struct type, "upreferences" go away.
5. Type refinement is completely gone, which should make LTO much MUCH faster
   in some common cases with C++ code.
6. Types are now generally immutable, so we can use "Type *" instead 
   "const Type *" everywhere.

Downsides of this patch are that it removes some functions from the C API,
so people using those will have to upgrade to (not yet added) new API.  
"LLVM 3.0" is the right time to do this.

There are still some cleanups pending after this, this patch is large enough
as-is.

llvm-svn: 134829
2011-07-09 17:41:24 +00:00
Frits van Bommel d097212a08 Add test cases for Jay's r129641 and fix a 32-bit-centric testcase in a file with a 64-bit datalayout.
llvm-svn: 129643
2011-04-16 14:31:50 +00:00
Chris Lattner a8fed47eed have instcombine preserve nsw/nuw/exact when sinking
common operations through a phi. 

llvm-svn: 125790
2011-02-17 23:01:49 +00:00
Chris Lattner abb8eb2c63 fix instcombine merging GEPs through a PHI to only make the
result inbounds if all of the inputs are inbounds.

llvm-svn: 125785
2011-02-17 22:21:26 +00:00
Chris Lattner d55581ded8 enhance FoldOpIntoPhi in instcombine to try harder when a phi has
multiple uses.  In some cases, all the uses are the same operation,
so instcombine can go ahead and promote the phi.  In the testcase
this pushes an add out of the loop.

llvm-svn: 123568
2011-01-16 05:28:59 +00:00
Duncan Sands 5ffc298bc7 In which I discover the existence of loops. Threading an operation
over a phi node by applying it to each operand may be wrong if the
operation and the phi node are mutually interdependent (the testcase
has a simple example of this).  So only do this transform if it would
be correct to perform the operation in each predecessor of the block
containing the phi, i.e. if the other operands all dominate the phi.
This should fix the FFMPEG snow.c regression reported by İsmail Dönmez.

llvm-svn: 119347
2010-11-16 12:16:38 +00:00
Duncan Sands f12ba1dfe1 Teach InstructionSimplify the trick of skipping incoming phi
values that are equal to the phi itself.

llvm-svn: 119161
2010-11-15 17:52:45 +00:00
Duncan Sands 01157b027b Move PHI tests to phi.ll, out of select.ll.
llvm-svn: 119153
2010-11-15 16:43:28 +00:00
Owen Anderson 064cb4c807 Add a test for PR4413, which was apparently fixed at some point in the past.
llvm-svn: 112987
2010-09-03 18:33:08 +00:00
Chris Lattner f6befffbb2 fix PR6512, a case where instcombine would incorrectly merge loads
from different addr spaces.

llvm-svn: 97813
2010-03-05 18:53:28 +00:00
Chris Lattner 0685be3441 enhance PHI slicing to handle the case when a slicable PHI is begin
used by a chain of other PHIs.

llvm-svn: 86503
2009-11-09 01:38:00 +00:00
Chris Lattner 2299d4b6d8 Teach an instcombine to not pull trunc instructions through PHI nodes
when both the source and dest are illegal types, since it would cause
the phi to grow (for example, we shouldn't transform test14b's phi to
a phi on i320).  This fixes an infinite loop on i686 bootstrap with
phi slicing turned on, so turn it back on.

llvm-svn: 86483
2009-11-08 21:20:06 +00:00
Chris Lattner a837e4db6b reapply r8644[3-5] with only the scary part
(SliceUpIllegalIntegerPHI) disabled.

llvm-svn: 86480
2009-11-08 19:23:30 +00:00
Daniel Dunbar 4c41373c56 Speculatively revert r8644[3-5], they seem to be leading to infinite loops in
llvm-gcc bootstrap.

llvm-svn: 86478
2009-11-08 17:52:47 +00:00
Chris Lattner 99db7963b4 another more interesting test.
llvm-svn: 86445
2009-11-08 08:36:40 +00:00
Chris Lattner 7c8b29ef61 feature test for the new transformation in r86443
llvm-svn: 86444
2009-11-08 08:30:58 +00:00
Chris Lattner c7a450b5b2 teach a couple of instcombine transformations involving PHIs to
not turn a PHI in a legal type into a PHI of an illegal type, and
add a new optimization that breaks up insane integer PHI nodes into
small pieces (PR3451).

llvm-svn: 86443
2009-11-08 08:21:13 +00:00
Chris Lattner 3e6398baa5 merge phi-merge.ll into phi.ll
I don't know what Dan wants to do with phi-merge-gep.ll, I'll let
him deal with it because instcombine may end up sinking these.

llvm-svn: 85739
2009-11-01 20:10:11 +00:00
Chris Lattner 328ef89bd1 when merging two loads, make sure to take the min of their alignment,
not the max.  This didn't matter until the previous patch because
instcombine would refuse to sink loads with differenting alignments.

llvm-svn: 85738
2009-11-01 20:07:07 +00:00
Chris Lattner 0b40a8bc0e fix a bug noticed by inspection: when instcombine sinks loads through
phis, it didn't preserve the alignment of the load.  This is a missed
optimization of the alignment is high and a miscompilation when the
alignment is low.

llvm-svn: 85736
2009-11-01 19:50:13 +00:00
Chris Lattner d162b5c955 convert to filecheck.
llvm-svn: 85734
2009-11-01 19:22:20 +00:00
Dan Gohman 72a13d2476 Use opt -S instead of piping bitcode output through llvm-dis.
llvm-svn: 81257
2009-09-08 22:34:10 +00:00
Dan Gohman 9737a63ed8 Change these tests to feed the assembly files to opt directly, instead
of using llvm-as, now that opt supports this.

llvm-svn: 81226
2009-09-08 16:50:01 +00:00
Chris Lattner 9d02a70a7d Teach inst combine to merge GEPs through PHIs. This is really
important because it is sinking the loads using the GEPs, but
not the GEPs themselves.  This triggers 647 times on 403.gcc
and makes the .s file much much nicer.  For example before:

        je      LBB1_87 ## bb78
LBB1_62:        ## bb77
        leal    84(%esi), %eax
LBB1_63:        ## bb79
        movl    (%eax), %eax
...
LBB1_87:        ## bb78
        movl    $0, 4(%esp)
        movl    %esi, (%esp)
        call    L_make_decl_rtl$stub
        jmp     LBB1_62 ## bb77


after:

        jne     LBB1_63 ## bb79
LBB1_62:        ## bb78
        movl    $0, 4(%esp)
        movl    %esi, (%esp)
        call    L_make_decl_rtl$stub
LBB1_63:        ## bb79
        movl    84(%esi), %eax

The input code was (and the GEPs are merged and
the PHI is now eliminated by instcombine):

        br i1 %tmp233, label %bb78, label %bb77
bb77:           
        %tmp234 = getelementptr %struct.tree_node* %t_addr.3, i32 0, i32 0, i32 22              
        br label %bb79
bb78:           
        call void @make_decl_rtl(%struct.tree_node* %t_addr.3, i8* null) nounwind
        %tmp235 = getelementptr %struct.tree_node* %t_addr.3, i32 0, i32 0, i32 22              
        br label %bb79
bb79:           
        %iftmp.12.0.in = phi %struct.rtx_def** [ %tmp235, %bb78 ], [ %tmp234, %bb77 ]           
        %iftmp.12.0 = load %struct.rtx_def** %iftmp.12.0.in             

llvm-svn: 60322
2008-12-01 02:34:36 +00:00
Tanya Lattner 5640bd186a Remove llvm-upgrade and update test cases.
llvm-svn: 47793
2008-03-01 09:15:35 +00:00
Reid Spencer ede8c3b92c For PR1319:
Make use of the END. facility on all files > 1K so that we aren't wasting CPU
cycles searching for RUN: lines that we'll never find.

llvm-svn: 36059
2007-04-15 07:38:21 +00:00
Reid Spencer 91948d4cad For PR1319:
Upgrade tests to work with new llvm.exp version of llvm_runtest.

llvm-svn: 36013
2007-04-14 20:13:02 +00:00
Reid Spencer 83b3d82672 Regression is gone, don't try to find it on clean target.
llvm-svn: 33296
2007-01-17 07:59:14 +00:00