diff options
| author | Jorropo <jorropo.pgm@gmail.com> | 2025-07-26 03:36:15 +0200 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2025-07-28 11:06:07 -0700 |
| commit | 94645d241320fe0617a4f158a4e1b64a643bb10f (patch) | |
| tree | 32e92cd7df7f8205f0308ee19dcbb2ec787b50e0 /src/cmd/compile | |
| parent | 10c5cf68d40e2b26336e4b4e59d4c2f3fc3f03b9 (diff) | |
| download | go-94645d241320fe0617a4f158a4e1b64a643bb10f.tar.xz | |
cmd/compile: rewrite cmov(x, x, cond) into x
I don't think branchelim will intentionally generate theses.
But at the time where branchelim is generating them they might different,
and through opt process they become the same value.
Change-Id: I4a19f1db14c08057b7e782a098f4c18ca36ab7fe
Reviewed-on: https://go-review.googlesource.com/c/go/+/690519
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Mark Freeman <mark@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/cmd/compile')
| -rw-r--r-- | src/cmd/compile/internal/ssa/_gen/generic.rules | 1 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/rewritegeneric.go | 10 |
2 files changed, 11 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules index b98dfae2d5..72d9677c5f 100644 --- a/src/cmd/compile/internal/ssa/_gen/generic.rules +++ b/src/cmd/compile/internal/ssa/_gen/generic.rules @@ -297,6 +297,7 @@ (CondSelect x _ (ConstBool [true ])) => x (CondSelect _ y (ConstBool [false])) => y +(CondSelect x x _) => x // signed integer range: ( c <= x && x (<|<=) d ) -> ( unsigned(x-c) (<|<=) unsigned(d-c) ) (AndB (Leq64 (Const64 [c]) x) ((Less|Leq)64 x (Const64 [d]))) && d >= c => ((Less|Leq)64U (Sub64 <x.Type> x (Const64 <x.Type> [c])) (Const64 <x.Type> [d-c])) diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go index 0b9f9c09f9..bdde103a1f 100644 --- a/src/cmd/compile/internal/ssa/rewritegeneric.go +++ b/src/cmd/compile/internal/ssa/rewritegeneric.go @@ -5722,6 +5722,16 @@ func rewriteValuegeneric_OpCondSelect(v *Value) bool { v.copyOf(y) return true } + // match: (CondSelect x x _) + // result: x + for { + x := v_0 + if x != v_1 { + break + } + v.copyOf(x) + return true + } // match: (CondSelect (Add8 <t> x (Const8 [1])) x bool) // cond: config.arch != "arm64" // result: (Add8 x (CvtBoolToUint8 <t> bool)) |