Commit Graph

6 Commits

Author SHA1 Message Date
Sanjay Patel cc29f4f2cb only propagate equality comparisons of FP values that we are certain are non-zero
This is a follow-on to r227491 which tightens the check for propagating FP
values. If a non-constant value happens to be a zero, we would hit the same
bug as before.

Bug noted and patch suggested by Eli Friedman.

llvm-svn: 230564
2015-02-25 22:46:08 +00:00
Sanjay Patel 4f07a56958 [GVN] don't propagate equality comparisons of FP zero (PR22376)
In http://reviews.llvm.org/D6911, we allowed GVN to propagate FP equalities
to allow some simple value range optimizations. But that introduced a bug
when comparing to -0.0 or 0.0: these compare equal even though they are not
bitwise identical.

This patch disallows propagating zero constants in equality comparisons. 
Fixes: http://llvm.org/bugs/show_bug.cgi?id=22376

Differential Revision: http://reviews.llvm.org/D7257

llvm-svn: 227491
2015-01-29 20:51:49 +00:00
Sanjay Patel 5f1d9eaad3 GVN: propagate equalities for floating point compares
Allow optimizations based on FP comparison values in the same way
as integers. 

This resolves PR17713:
http://llvm.org/bugs/show_bug.cgi?id=17713

Differential Revision: http://reviews.llvm.org/D6911

llvm-svn: 225660
2015-01-12 19:29:48 +00:00
Stephen Lin a76289aa1b Catch more CHECK that can be converted to CHECK-LABEL in Transforms for easier debugging. No functionality change.
This conversion 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/;\(.*\)\([A-Za-z0-9_]*\):\( *\)define\([^@]*\)@$FUNC\([( ]*\)\$/;\1\2-LABEL:\3define\4@$FUNC(/g" $TEMP
      done
      mv $TEMP $NAME
    fi
  done

llvm-svn: 186269
2013-07-14 01:50:49 +00:00
Dmitri Gribenko d7beca87f5 Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID
This is done to avoid odd test failures, like the one fixed in r171243.

My previous regex was not good enough to find these.

llvm-svn: 171343
2013-01-01 13:57:25 +00:00
Rafael Espindola cc80cdebb9 Teach GVN to reason about edges dominating uses. This allows it to handle cases
where some fact lake a=b dominates a use in a phi, but doesn't dominate the
basic block itself.

This feature could also be implemented by splitting critical edges, but at least
with the current algorithm reasoning about the dominance directly is faster.

The time for running "opt -O2" in the testcase in pr10584 is 1.003 times slower
and on gcc as a single file it is 1.0007 times faster.

llvm-svn: 162023
2012-08-16 15:09:43 +00:00