Commit Graph

6 Commits

Author SHA1 Message Date
Benjamin Kramer 594f963ea6 X86: If we have an instruction that sets a flag and a zero test on the input of that instruction try to eliminate the test.
For example
	tzcntl	%edi, %ebx
	testl %edi, %edi
	je	.label

can be rewritten into
	tzcntl	%edi, %ebx
	jb 	.label

A minor complication is that tzcnt sets CF instead of ZF when the input
is zero, we have to rewrite users of the flags from ZF to CF. Currently
we recognize patterns using lzcnt, tzcnt and popcnt.

Differential Revision: http://reviews.llvm.org/D3454

llvm-svn: 208788
2014-05-14 16:14:45 +00:00
Stephen Lin d24ab20e9b Mass update to CodeGen tests to use CHECK-LABEL for labels corresponding to function definitions for more informative error messages. No functionality change and all updated tests passed locally.
This update was done with the following bash script:

  find test/CodeGen -name "*.ll" | \
  while read NAME; do
    echo "$NAME"
    if ! grep -q "^; *RUN: *llc.*debug" $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
      sed -i '' "s/;\(.*\)-LABEL-LABEL:/;\1-LABEL:/" $TEMP
      sed -i '' "s/;\(.*\)-NEXT-LABEL:/;\1-NEXT:/" $TEMP
      sed -i '' "s/;\(.*\)-NOT-LABEL:/;\1-NOT:/" $TEMP
      sed -i '' "s/;\(.*\)-DAG-LABEL:/;\1-DAG:/" $TEMP
      mv $TEMP $NAME
    fi
  done

llvm-svn: 186280
2013-07-14 06:24:09 +00:00
David Majnemer 7ea2a52a0c X86: Remove test instructions proceeding shift by immediate instructions
Allow LLVM to take advantage of shift instructions that set the ZF flag,
making instructions that test the destination superfluous.

llvm-svn: 182454
2013-05-22 08:13:02 +00:00
Benjamin Kramer 41942fb37a Relax CHECK-NEXTs a bit to cope with atom's return nop padding.
llvm-svn: 181999
2013-05-16 11:46:50 +00:00
David Majnemer 37d3825022 Set an explicit triple for this test.
This allows the test to correctly check symbol names.

llvm-svn: 181939
2013-05-15 22:23:21 +00:00
David Majnemer 8f16974273 X86: Remove redundant test instructions
Increase the number of instructions LLVM recognizes as setting the ZF
flag. This allows us to remove test instructions that redundantly
recalculate the flag.

llvm-svn: 181937
2013-05-15 22:03:08 +00:00