Commit Graph

4 Commits

Author SHA1 Message Date
Hans Wennborg dcc2500452 X86: More efficient legalization of wide integer compares
In particular, this makes the code for 64-bit compares on 32-bit targets
much more efficient.

Example:

  define i32 @test_slt(i64 %a, i64 %b) {
  entry:
    %cmp = icmp slt i64 %a, %b
    br i1 %cmp, label %bb1, label %bb2
  bb1:
    ret i32 1
  bb2:
    ret i32 2
  }

Before this patch:

  test_slt:
          movl    4(%esp), %eax
          movl    8(%esp), %ecx
          cmpl    12(%esp), %eax
          setae   %al
          cmpl    16(%esp), %ecx
          setge   %cl
          je      .LBB2_2
          movb    %cl, %al
  .LBB2_2:
          testb   %al, %al
          jne     .LBB2_4
          movl    $1, %eax
          retl
  .LBB2_4:
          movl    $2, %eax
          retl

After this patch:

  test_slt:
          movl    4(%esp), %eax
          movl    8(%esp), %ecx
          cmpl    12(%esp), %eax
          sbbl    16(%esp), %ecx
          jge     .LBB1_2
          movl    $1, %eax
          retl
  .LBB1_2:
          movl    $2, %eax
          retl

Differential Revision: http://reviews.llvm.org/D14496

llvm-svn: 253572
2015-11-19 16:35:08 +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
Tim Northover 6c647eae8b X86: remove temporary atomicrmw used during lowering.
We construct a temporary "atomicrmw xchg" instruction when lowering atomic
stores for widths that aren't supported natively. This isn't on the top-level
worklist though, so it won't be removed automatically and we have to do it
ourselves once that itself has been lowered.

Thanks Saleem for pointing this out!

llvm-svn: 212948
2014-07-14 15:31:13 +00:00
Tim Northover 277066ab43 X86: expand atomics in IR instead of as MachineInstrs.
The logic for expanding atomics that aren't natively supported in
terms of cmpxchg loops is much simpler to express at the IR level. It
also allows the normal optimisations and CodeGen improvements to help
out with atomics, instead of using a limited set of possible
instructions..

rdar://problem/13496295

llvm-svn: 212119
2014-07-01 18:53:31 +00:00