diff options
| author | David Chase <drchase@google.com> | 2020-12-30 12:05:57 -0500 |
|---|---|---|
| committer | David Chase <drchase@google.com> | 2021-01-13 02:40:43 +0000 |
| commit | 9a19481acb93114948503d935e10f6985ff15843 (patch) | |
| tree | bdccf0f8413dfb40ca93862f642968229fc35a26 /src/cmd/compile/internal/ssa/rewriteS390X.go | |
| parent | d9acf6f3a3758c3096ee5ef5a24c2bc5df9d9c8b (diff) | |
| download | go-9a19481acb93114948503d935e10f6985ff15843.tar.gz go-9a19481acb93114948503d935e10f6985ff15843.zip | |
[dev.regabi] cmd/compile: make ordering for InvertFlags more stable
Current many architectures use a rule along the lines of
// Canonicalize the order of arguments to comparisons - helps with CSE.
((CMP|CMPW) x y) && x.ID > y.ID => (InvertFlags ((CMP|CMPW) y x))
to normalize comparisons as much as possible for CSE. Replace the
ID comparison with something less variable across compiler changes.
This helps avoid spurious failures in some of the codegen-comparison
tests (though the current choice of comparison is sensitive to Op
ordering).
Two tests changed to accommodate modified instruction choice.
Change-Id: Ib35f450bd2bae9d4f9f7838ceaf7ec682bcf1e1a
Reviewed-on: https://go-review.googlesource.com/c/go/+/280155
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Diffstat (limited to 'src/cmd/compile/internal/ssa/rewriteS390X.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/rewriteS390X.go | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/src/cmd/compile/internal/ssa/rewriteS390X.go b/src/cmd/compile/internal/ssa/rewriteS390X.go index a9722b820c..b52a1b6745 100644 --- a/src/cmd/compile/internal/ssa/rewriteS390X.go +++ b/src/cmd/compile/internal/ssa/rewriteS390X.go @@ -6332,12 +6332,12 @@ func rewriteValueS390X_OpS390XCMP(v *Value) bool { return true } // match: (CMP x y) - // cond: x.ID > y.ID + // cond: canonLessThan(x,y) // result: (InvertFlags (CMP y x)) for { x := v_0 y := v_1 - if !(x.ID > y.ID) { + if !(canonLessThan(x, y)) { break } v.reset(OpS390XInvertFlags) @@ -6389,12 +6389,12 @@ func rewriteValueS390X_OpS390XCMPU(v *Value) bool { return true } // match: (CMPU x y) - // cond: x.ID > y.ID + // cond: canonLessThan(x,y) // result: (InvertFlags (CMPU y x)) for { x := v_0 y := v_1 - if !(x.ID > y.ID) { + if !(canonLessThan(x, y)) { break } v.reset(OpS390XInvertFlags) @@ -6624,12 +6624,12 @@ func rewriteValueS390X_OpS390XCMPW(v *Value) bool { return true } // match: (CMPW x y) - // cond: x.ID > y.ID + // cond: canonLessThan(x,y) // result: (InvertFlags (CMPW y x)) for { x := v_0 y := v_1 - if !(x.ID > y.ID) { + if !(canonLessThan(x, y)) { break } v.reset(OpS390XInvertFlags) @@ -6721,12 +6721,12 @@ func rewriteValueS390X_OpS390XCMPWU(v *Value) bool { return true } // match: (CMPWU x y) - // cond: x.ID > y.ID + // cond: canonLessThan(x,y) // result: (InvertFlags (CMPWU y x)) for { x := v_0 y := v_1 - if !(x.ID > y.ID) { + if !(canonLessThan(x, y)) { break } v.reset(OpS390XInvertFlags) |