Commit Graph

6 Commits

Author SHA1 Message Date
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
Sanjoy Das dcf2651043 Teach IRCE to look at branch weights when recognizing range checks
Splitting a loop to make range checks redundant is profitable only if
the range check "never" fails. Make this fact a part of recognizing a
range check -- a branch is a range check only if it is expected to
pass (via branch_weights metadata).

Differential Revision: http://reviews.llvm.org/D7192

llvm-svn: 227249
2015-01-27 21:38:12 +00:00
Sanjoy Das a1837a342d Add a new pass "inductive range check elimination"
IRCE eliminates range checks of the form

  0 <= A * I + B < Length

by splitting a loop's iteration space into three segments in a way
that the check is completely redundant in the middle segment.  As an
example, IRCE will convert

  len = < known positive >
  for (i = 0; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }

to

  len = < known positive >
  limit = smin(n, len)
  // no first segment
  for (i = 0; i < limit; i++) {
    if (0 <= i && i < len) { // this check is fully redundant
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }
  for (i = limit; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }


IRCE can deal with multiple range checks in the same loop (it takes
the intersection of the ranges that will make each of them redundant
individually).

Currently IRCE does not do any profitability analysis.  That is a
TODO.

Please note that the status of this pass is *experimental*, and it is
not part of any default pass pipeline.  Having said that, I will love
to get feedback and general input from people interested in trying
this out.

This pass was originally r226201.  It was reverted because it used C++
features not supported by MSVC 2012.

Differential Revision: http://reviews.llvm.org/D6693

llvm-svn: 226238
2015-01-16 01:03:22 +00:00
Sanjoy Das 7f62ac8e4d Revert r226201 (Add a new pass "inductive range check elimination")
The change used C++11 features not supported by MSVC 2012.  I will fix
the change to use things supported MSVC 2012 and recommit shortly.

llvm-svn: 226216
2015-01-15 22:18:10 +00:00
Sanjoy Das 7059e2959d Add a new pass "inductive range check elimination"
IRCE eliminates range checks of the form

  0 <= A * I + B < Length

by splitting a loop's iteration space into three segments in a way
that the check is completely redundant in the middle segment.  As an
example, IRCE will convert

  len = < known positive >
  for (i = 0; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }

to

  len = < known positive >
  limit = smin(n, len)
  // no first segment
  for (i = 0; i < limit; i++) {
    if (0 <= i && i < len) { // this check is fully redundant
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }
  for (i = limit; i < n; i++) {
    if (0 <= i && i < len) {
      do_something();
    } else {
      throw_out_of_bounds();
    }
  }


IRCE can deal with multiple range checks in the same loop (it takes
the intersection of the ranges that will make each of them redundant
individually).

Currently IRCE does not do any profitability analysis.  That is a
TODO.

Please note that the status of this pass is *experimental*, and it is
not part of any default pass pipeline.  Having said that, I will love
to get feedback and general input from people interested in trying
this out.

Differential Revision: http://reviews.llvm.org/D6693

llvm-svn: 226201
2015-01-15 20:45:46 +00:00