Commit Graph

8 Commits

Author SHA1 Message Date
Philip Reames a0c9f6e736 [LVI] Fix a bug which prevented use of !range metadata within a query
The diff is relatively large since I took a chance to rearrange the code I had to touch in a more obvious way, but the key bit is merely using the !range metadata when we can't analyze the instruction further.  The previous !range metadata code was essentially just dead since no binary operator or cast will have !range metadata (per Verifier) and it was otherwise dropped on the floor.

llvm-svn: 262751
2016-03-04 22:27:39 +00:00
Philip Reames eb3e9dad7f [LVI/CVP] Teach LVI about range metadata
Somewhat shockingly for an analysis pass which is computing constant ranges, LVI did not understand the ranges provided by range metadata.

As part of this change, I included a change to CVP primarily because doing so made it much easier to write small self contained test cases. CVP was previously only handling the non-local operand case, but given that LVI can sometimes figure out information about instructions standalone, I don't see any reason to restrict this.  There could possibly be a compile time impact from this, but I suspect it should be minimal.  If anyone has an example which substaintially regresses, please let me know.  I could restrict the block local handling to ICmps feeding Terminator instructions if needed.  

Note that this patch continues a somewhat bad practice in LVI. In many cases, we know facts about values, and separate context sensitive facts about values. LVI makes no effort to distinguish and will frequently cache the same value fact repeatedly for different contexts. I would like to change this, but that's a large enough change that I want it to go in separately with clear documentation of what's changing. Other examples of this include the non-null handling, and arguments.

As a meta comment: the entire motivation of this change was being able to write smaller (aka reasonable sized) test cases for a future patch teaching LVI about select instructions.

Differential Revision: http://reviews.llvm.org/D13543

llvm-svn: 251606
2015-10-29 03:57:17 +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
Nuno Lopes 8650fb8e0e make LazyValueInfo analyze the default case of switch statements (we know that in the default branch the value cannot be any of the switch cases)
llvm-svn: 159353
2012-06-28 16:13:37 +00:00
Nuno Lopes e6e049020b make LVI::getEdgeValue() always intersect the constraints of the edge with the range of the block. Previously it was only performing the intersection for a few cases, thus losing precision
llvm-svn: 159320
2012-06-28 01:16:18 +00:00
Nuno Lopes ac59380dfd allow LazyValueInfo::getEdgeValue() to reason about multiple edges from the same switch instruction by doing union of ranges (which may still be conservative, but it's more aggressive than before)
llvm-svn: 157071
2012-05-18 21:02:10 +00:00
Nuno Lopes b63d6cdf79 add test case for bugfix in r157032
llvm-svn: 157058
2012-05-18 17:44:58 +00:00
Benjamin Kramer d9d80b1dde LVI: Recognize the form instcombine canonicalizes range checks into when forming constant ranges.
This could probably be made a lot smarter, but this is a common case and doesn't require LVI to scan a lot
of code. With this change CVP can optimize away the "shift == 0" case in Hashing.h that only gets hit when
"shift" is in a range not containing 0.

llvm-svn: 151919
2012-03-02 15:34:43 +00:00