Commit Graph

9 Commits

Author SHA1 Message Date
David Majnemer
fca9c7b21c InstSimplify: Try to bring back the rest of r223583
This reverts r223624 with a small tweak, hopefully this will make stage3
equivalent.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223679 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-08 18:30:43 +00:00
NAKAMURA Takumi
e4a5390406 Revert a part of r223583, for now. It seems causing different emission between stage2(gcc-clang) and stage3 clang. Investigating.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223624 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-08 02:07:22 +00:00
David Majnemer
620e8763ec InstSimplify: Optimize away useless unsigned comparisons
Code like X < Y && Y == 0 should always be folded away to false.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223583 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-06 10:51:40 +00:00
David Majnemer
7eca618dfc InstSimplify: Simplify (sub 0, X) -> X if it's NUW
This is a generalization of the X - (0 - Y) -> X transform.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222611 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-22 07:15:16 +00:00
David Majnemer
c3e70ca886 InstSimplify: Simplify trivial and/or of icmps
Some ICmpInsts when anded/ored with another ICmpInst trivially reduces
to true or false depending on whether or not all integers or no integers
satisfy the intersected/unioned range.

This sort of trivial looking code can come about when InstCombine
performs a range reduction-type operation on sdiv and the like.

This fixes PR20916.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217750 91177308-0d34-0410-b5e6-96231b3b80d8
2014-09-15 08:15:28 +00:00
David Majnemer
ec7ee07036 InstSimplify: Simplify (X - (0 - Y)) if the second sub is NUW
If the NUW bit is set for 0 - Y, we know that all values for Y other
than 0 would produce a poison value.  This allows us to replace (0 - Y)
with 0 in the expression (X - (0 - Y)) which will ultimately leave us
with X.

This partially fixes PR20189.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214384 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-31 04:49:18 +00:00
Stephen Lin
39f4e8d9cc 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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186268 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-14 01:42:54 +00:00
Duncan Sands
4604fc7791 A shift of a power of two is a power of two or zero.
For completeness - not spotted in the wild.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143211 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-28 18:30:05 +00:00
Duncan Sands
dd3149d579 The maximum power of 2 dividing a power of 2 is itself. This occurs
in 403.gcc and was spotted by my super-optimizer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143054 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-26 20:55:21 +00:00