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| author | Josh Bleecher Snyder <josharian@gmail.com> | 2017-03-24 10:36:13 -0700 |
|---|---|---|
| committer | Josh Bleecher Snyder <josharian@gmail.com> | 2017-03-24 18:00:15 +0000 |
| commit | e00e57d67cea33d4faef8506ced6f3c2416cfd15 (patch) | |
| tree | e84f3ef7ea308ec55e7953f409edba1ab8011cf6 /src/cmd/compile/internal/ssa/deadcode.go | |
| parent | ad8c17b70328b8771ed5bbfe9161cb98f1995b84 (diff) | |
| download | go-e00e57d67cea33d4faef8506ced6f3c2416cfd15.tar.gz go-e00e57d67cea33d4faef8506ced6f3c2416cfd15.zip | |
cmd/compile: ignore all unreachable values during simple phi insertion
Simple phi insertion already had a heuristic to check
for dead blocks, namely having no predecessors.
When we stopped generating code for dead blocks,
we eliminated some values contained in more subtle
dead blocks, which confused phi insertion.
Compensate by beefing up the reachability check.
Fixes #19678
Change-Id: I0081e4a46f7ce2f69b131a34a0553874a0cb373e
Reviewed-on: https://go-review.googlesource.com/38602
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src/cmd/compile/internal/ssa/deadcode.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/deadcode.go | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/src/cmd/compile/internal/ssa/deadcode.go b/src/cmd/compile/internal/ssa/deadcode.go index ce786a964b..b24ecaa4c4 100644 --- a/src/cmd/compile/internal/ssa/deadcode.go +++ b/src/cmd/compile/internal/ssa/deadcode.go @@ -6,13 +6,13 @@ package ssa // findlive returns the reachable blocks and live values in f. func findlive(f *Func) (reachable []bool, live []bool) { - reachable = reachableBlocks(f) + reachable = ReachableBlocks(f) live = liveValues(f, reachable) return } -// reachableBlocks returns the reachable blocks in f. -func reachableBlocks(f *Func) []bool { +// ReachableBlocks returns the reachable blocks in f. +func ReachableBlocks(f *Func) []bool { reachable := make([]bool, f.NumBlocks()) reachable[f.Entry.ID] = true p := []*Block{f.Entry} // stack-like worklist @@ -106,7 +106,7 @@ func deadcode(f *Func) { } // Find reachable blocks. - reachable := reachableBlocks(f) + reachable := ReachableBlocks(f) // Get rid of edges from dead to live code. for _, b := range f.Blocks { |