Commit Graph

22 Commits

Author SHA1 Message Date
Sanjay Patel 92938657a0 [DAGCombiner] fold binops with constant into select-of-constants
This is part of the ongoing attempt to improve select codegen for all targets and select 
canonicalization in IR (see D24480 for more background). The transform is a subset of what
is done in InstCombine's FoldOpIntoSelect().

I first noticed a regression in the x86 avx512-insert-extract.ll tests with a patch that 
hopes to convert more selects to basic math ops. This appears to be a general missing DAG
transform though, so I added tests for all standard binops in rL296621 
(PowerPC was chosen semi-randomly; it has scripted FileCheck support, but so do ARM and x86).

The poor output for "sel_constants_shl_constant" is tracked with:
https://bugs.llvm.org/show_bug.cgi?id=32105

Differential Revision: https://reviews.llvm.org/D30502

llvm-svn: 296699
2017-03-01 22:51:31 +00:00
James Molloy 4d86bed0bb [Thumb] Select (CMPZ X, -C) -> (CMPZ (ADDS X, C), 0)
The CMPZ #0 disappears during peepholing, leaving just a tADDi3, tADDi8 or t2ADDri. This avoids having to materialize the expensive negative constant in Thumb-1, and allows a shrinking from a 32-bit CMN to a 16-bit ADDS in Thumb-2.

llvm-svn: 281040
2016-09-09 12:52:24 +00:00
David Blaikie a79ac14fa6 [opaque pointer type] Add textual IR support for explicit type parameter to load instruction
Essentially the same as the GEP change in r230786.

A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)

import fileinput
import sys
import re

pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")

for line in sys.stdin:
  sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7649

llvm-svn: 230794
2015-02-27 21:17:42 +00:00
Oliver Stannard d29db9b949 Fix optimisations of SELECT_CC which assumed result is boolean
Some optimisations in DAGCombiner cause miscompilations for targets that use
TargetLowering::UndefinedBooleanContent, because they assume that the results
of a SELECT_CC node are boolean values, and can be safely ANDed, ORed and
XORed. These optimisations are only valid for targets that use
ZeroOrOneBooleanContent or ZeroOrNegativeOneBooleanContent.

This is a follow-up to D6210/r221693.

llvm-svn: 222123
2014-11-17 10:49:31 +00:00
Oliver Stannard 8c2c67e63c LLVM incorrectly folds xor into select
LLVM replaces the SelectionDAG pattern (xor (set_cc cc x y) 1) with
(set_cc !cc x y), which is only correct when the xor has type i1.
Instead, we should check that the constant operand to the xor is all
ones.

llvm-svn: 221693
2014-11-11 17:36:01 +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
Jakob Stoklund Olesen f831059f60 Use predication instead of pseudo-opcodes when folding into MOVCC.
Now that it is possible to dynamically tie MachineInstr operands,
predicated instructions are possible in SSA form:

  %vreg3<def> = SUBri %vreg1, -2147483647, pred:14, pred:%noreg, %opt:%noreg
  %vreg4<def,tied1> = MOVCCr %vreg3<tied0>, %vreg1, %pred:12, pred:%CPSR

Becomes a predicated SUBri with a tied imp-use:

  SUBri %vreg1, -2147483647, pred:13, pred:%CPSR, opt:%noreg, %vreg1<imp-use,tied0>

This means that any instruction that is safe to move can be folded into
a MOVCC, and the *CC pseudo-instructions are no longer needed.

The test case changes reflect that Thumb2SizeReduce recognizes the
predicated instructions. It didn't understand the pseudos.

llvm-svn: 163274
2012-09-05 23:58:02 +00:00
Jakob Stoklund Olesen dded061f85 Also combine zext/sext into selects for ARM.
This turns common i1 patterns into predicated instructions:

  (add (zext cc), x) -> (select cc (add x, 1), x)
  (add (sext cc), x) -> (select cc (add x, -1), x)

For a function like:

  unsigned f(unsigned s, int x) {
    return s + (x>0);
  }

We now produce:

  cmp r1, #0
  it  gt
  addgt.w r0, r0, #1

Instead of:

  movs  r2, #0
  cmp r1, #0
  it  gt
  movgt r2, #1
  add r0, r2

llvm-svn: 162177
2012-08-18 21:25:22 +00:00
Jakob Stoklund Olesen aab43dbfbb Also pass logical ops to combineSelectAndUse.
Add these transformations to the existing add/sub ones:

  (and (select cc, -1, c), x) -> (select cc, x, (and, x, c))
  (or  (select cc, 0, c), x)  -> (select cc, x, (or, x, c))
  (xor (select cc, 0, c), x)  -> (select cc, x, (xor, x, c))

The selects can then be transformed to a single predicated instruction
by peephole.

This transformation will make it possible to eliminate the ISD::CAND,
COR, and CXOR custom DAG nodes.

llvm-svn: 162176
2012-08-18 21:25:16 +00:00
Jakob Stoklund Olesen 7b1a2e8f02 Avoid folding ADD instructions with FI operands.
PEI can't handle the pseudo-instructions. This can be removed when the
pseudo-instructions are replaced by normal predicated instructions.

Fixes PR13628.

llvm-svn: 162130
2012-08-17 20:55:34 +00:00
Jakob Stoklund Olesen 0ea1fce6b4 Add ADD and SUB to the predicable ARM instructions.
It is not my plan to duplicate the entire ARM instruction set with
predicated versions. We need a way of representing predicated
instructions in SSA form without requiring a separate opcode.

Then the pseudo-instructions can go away.

llvm-svn: 162061
2012-08-16 23:21:55 +00:00
Jakob Stoklund Olesen 6cb96120f1 Fold predicable instructions into MOVCC / t2MOVCC.
The ARM select instructions are just predicated moves. If the select is
the only use of an operand, the instruction defining the operand can be
predicated instead, saving one instruction and decreasing register
pressure.

This implementation can turn AND/ORR/EOR instructions into their
corresponding ANDCC/ORRCC/EORCC variants. Ideally, we should be able to
predicate any instruction, but we don't yet support predicated
instructions in SSA form.

llvm-svn: 161994
2012-08-15 22:16:39 +00:00
Chad Rosier cbf45a6d8a Fix test case from r153135.
llvm-svn: 153140
2012-03-20 21:49:54 +00:00
Evan Cheng e87681cf34 Optimize a couple of common patterns involving conditional moves where the false
value is zero. Instead of a cmov + op, issue an conditional op instead. e.g.
    cmp   r9, r4
    mov   r4, #0
    moveq r4, #1 
    orr   lr, lr, r4

should be:
    cmp   r9, r4
    orreq lr, lr, #1

That is, optimize (or x, (cmov 0, y, cond)) to (or.cond x, y). Similarly extend
this to xor as well as (and x, (cmov -1, y, cond)) => (and.cond x, y).

It's possible to extend this to ADD and SUB but I don't think they are common.

rdar://8659097

llvm-svn: 151224
2012-02-23 01:19:06 +00:00
Jim Grosbach 581da64241 Simplify printing of ARM shifted immediates.
Print shifted immediate values directly rather than as a payload+shifter
value pair. This makes for more readable output assembly code, simplifies
the instruction printer, and is consistent with how Thumb immediates are
 displayed.

llvm-svn: 134902
2011-07-11 16:48:36 +00:00
Johnny Chen 293875ef55 Fix test-llvm failures.
llvm-svn: 128906
2011-04-05 18:41:40 +00:00
Evan Cheng 7f8ab6ee8b Remove ARM isel hacks that fold large immediates into a pair of add, sub, and,
and xor. The 32-bit move immediates can be hoisted out of loops by machine
LICM but the isel hacks were preventing them.

Instead, let peephole optimization pass recognize registers that are defined by
immediates and the ARM target hook will fold the immediates in.

Other changes include 1) do not fold and / xor into cmp to isel TST / TEQ
instructions if there are multiple uses. This happens when the 'and' is live
out, machine sink would have sinked the computation and that ends up pessimizing
code. The peephole pass would recognize situations where the 'and' can be
toggled to define CPSR and eliminate the comparison anyway.

2) Move peephole pass to after machine LICM, sink, and CSE to avoid blocking
important optimizations.

rdar://8663787, rdar://8241368

llvm-svn: 119548
2010-11-17 20:13:28 +00:00
Evan Cheng 0fc8084a64 Add conditional mvn instructions.
llvm-svn: 118935
2010-11-12 22:42:47 +00:00
Dan Gohman c8054d90fb Eliminate more uses of llvm-as and llvm-dis.
llvm-svn: 81293
2009-09-09 00:09:15 +00:00
Chris Lattner 7b87e542dc add no-unwind, remove duplicate run line.
llvm-svn: 66775
2009-03-12 05:56:37 +00:00
Dan Gohman f9dd170e36 Convert tests using "| wc -l | grep ..." to use the count script.
llvm-svn: 41097
2007-08-15 13:36:28 +00:00
Evan Cheng 5fcb5a5c74 New tests.
llvm-svn: 37686
2007-06-21 07:40:00 +00:00