Commit Graph

19 Commits

Author SHA1 Message Date
Sanjay Patel 93e64dd9a1 [PatternMatch] allow undef elements when matching vector FP +0.0
This continues the FP constant pattern matching improvements from:
https://reviews.llvm.org/rL327627
https://reviews.llvm.org/rL327339
https://reviews.llvm.org/rL327307

Several integer constant matchers also have this ability. I'm
separating matching of integer/pointer null from FP positive zero
and renaming/commenting to make the functionality clearer.

llvm-svn: 328461
2018-03-25 21:16:33 +00:00
Sanjay Patel c84b48ec29 [InstSimplify, InstCombine] add/update tests with FP +0.0 vector with undef; NFC
llvm-svn: 328455
2018-03-25 17:48:20 +00:00
Sanjay Patel 95ec4a4dfe [InstSimplify] loosen FMF for sqrt(X) * sqrt(X) --> X
As shown in the code comment, we don't need all of 'fast', 
but we do need reassoc + nsz + nnan.

Differential Revision: https://reviews.llvm.org/D43765

llvm-svn: 327796
2018-03-18 14:12:25 +00:00
Sanjay Patel a4f42f2cfd [PatternMatch, InstSimplify] allow undef elements when matching any vector FP zero
This matcher implementation appears to be slightly more efficient than 
the generic constant check that it is replacing because every use was 
for matching FP patterns, but the previous code would check int and 
pointer type nulls too. 

llvm-svn: 327627
2018-03-15 14:29:27 +00:00
Sanjay Patel 8f063d0c70 [InstSimplify] remove 'nsz' requirement for frem 0, X
From the LangRef definition for frem: 
"The value produced is the floating-point remainder of the two operands. 
This is the same output as a libm ‘fmod‘ function, but without any 
possibility of setting errno. The remainder has the same sign as the 
dividend. This instruction is assumed to execute in the default 
floating-point environment."

llvm-svn: 327626
2018-03-15 14:04:31 +00:00
Sanjay Patel e4e3f79b83 [InstSimplify] add tests for frem and vectors with undef; NFC
These should all be folded. The vector tests need to have
m_AnyZero updated to ignore undef elements, but we need to
be careful not to return the existing value in that case
and unintentionally propagate undef.

llvm-svn: 327585
2018-03-14 22:45:58 +00:00
Sanjay Patel 11f7f9908b [InstSimplify] fix folds for (0.0 - X) + X --> 0 (PR27151)
As shown in:
https://bugs.llvm.org/show_bug.cgi?id=27151
...the existing fold could miscompile when X is NaN.

The fold was also dependent on 'ninf' but that's not necessary.

From IEEE-754 (with default rounding which we can assume for these opcodes):
"When the sum of two operands with opposite signs (or the difference of two 
operands with like signs) is exactly zero, the sign of that sum (or difference) 
shall be +0...However, x + x = x − (−x) retains the same sign as x even when 
x is zero."

llvm-svn: 327575
2018-03-14 21:23:27 +00:00
Sanjay Patel fd82fd000c [InstSimplify] add tests to show missing/broken fadd folds (PR27151, PR26958); NFC
llvm-svn: 327554
2018-03-14 18:52:40 +00:00
Sanjay Patel e011d7964d [InstSimplify] regenerate checks; NFC
llvm-svn: 327553
2018-03-14 18:49:57 +00:00
Sanjay Patel db53d1847b [InstSimplify] sqrt(X) * sqrt(X) --> X
This was misplaced in InstCombine. We can loosen the FMF as a follow-up step.

llvm-svn: 325965
2018-02-23 22:20:13 +00:00
Sanjay Patel 69632447b1 [InstSimplify] regenerate checks using a script
I didn't notice any significant changes in the actual checks here;
all of these tests already used FileCheck, so a script can batch
update them in one shot.

This commit is just to show the value of automating this process: 
We have uniform formatting as opposed to a mish-mash of check
structure that changes based on individual prefs and the current
fashion. This makes it simpler to update when we find a bug or
make an enhancement.

llvm-svn: 264457
2016-03-25 20:12:25 +00:00
Benjamin Kramer 6bb15021b3 [InstSimplify] Restore fsub 0.0, (fsub 0.0, X) ==> X optzn
I accidentally removed this in r262212 but there was no test coverage to
detect it.

llvm-svn: 262215
2016-02-29 12:18:25 +00:00
Benjamin Kramer 1ee59cba5d [InstSimplify] Allow folding of fdiv X, X with just NaNs ignored
Any combination of +-inf/+-inf is NaN so it's already ignored with
nnan and we can skip checking for ninf. Also rephrase logic in comments
a bit.

llvm-svn: 239821
2015-06-16 14:57:29 +00:00
Benjamin Kramer 228680ded8 [InstSimplify] fsub nnan x, x -> 0.0 is valid without ninf
Both inf - inf and (-inf) - (-inf) are NaN, so it's already covered by
nnan.

llvm-svn: 239702
2015-06-14 21:01:20 +00:00
Benjamin Kramer 4f0524614e [InstSimplify] Add self-fdiv identities for -ffinite-math-only.
When NaNs and Infs are ignored we can fold
 X /  X -> 1.0
-X /  X -> -1.0
 X / -X -> -1.0

llvm-svn: 239701
2015-06-14 18:53:58 +00:00
Mehdi Amini cd3ca6f7dd InstSimplify: simplify 0 / X if nnan and nsz
From: Fiona Glaser <fglaser@apple.com>
llvm-svn: 230238
2015-02-23 18:30:25 +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
Michael Ilseman bb6f691b01 Added a slew of SimplifyInstruction floating-point optimizations, many of which take advantage of fast-math flags. Test cases included.
fsub X, +0 ==> X
  fsub X, -0 ==> X, when we know X is not -0
  fsub +/-0.0, (fsub -0.0, X) ==> X
  fsub nsz +/-0.0, (fsub +/-0.0, X) ==> X
  fsub nnan ninf X, X ==> 0.0
  fadd nsz X, 0 ==> X
  fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
    where nnan and ninf have to occur at least once somewhere in this expression
  fmul X, 1.0 ==> X

llvm-svn: 169940
2012-12-12 00:27:46 +00:00
Michael Ilseman 6cdacff2d0 Fast-math test for SimplifyInstruction: fold multiply by 0
Applied the patch, rather than committing it.

llvm-svn: 168656
2012-11-27 01:00:22 +00:00