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| author | Giovanni Bajo <rasky@develer.com> | 2018-04-15 16:03:30 +0200 |
|---|---|---|
| committer | Giovanni Bajo <rasky@develer.com> | 2018-04-29 09:38:18 +0000 |
| commit | 6d379add0fefcc17ed7b763078526800a3c1d705 (patch) | |
| tree | faeb34f011cf8637601357d9f4a6fc5d6b4e4635 /src/cmd/compile/internal/ssa/prove.go | |
| parent | 980fdb8dd5fe0151a9b7e84ec6b8c20a11727521 (diff) | |
| download | go-6d379add0fefcc17ed7b763078526800a3c1d705.tar.gz go-6d379add0fefcc17ed7b763078526800a3c1d705.zip | |
cmd/compile: in prove, detect loops with negative increments
To be effective, this also requires being able to relax constraints
on min/max bound inclusiveness; they are now exposed through a flags,
and prove has been updated to handle it correctly.
Change-Id: I3490e54461b7b9de8bc4ae40d3b5e2fa2d9f0556
Reviewed-on: https://go-review.googlesource.com/104041
Run-TryBot: Giovanni Bajo <rasky@develer.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Diffstat (limited to 'src/cmd/compile/internal/ssa/prove.go')
| -rw-r--r-- | src/cmd/compile/internal/ssa/prove.go | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index 536cfcebf0..0767be7d57 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -799,8 +799,17 @@ func addIndVarRestrictions(ft *factsTable, b *Block, iv indVar) { d |= unsigned } - addRestrictions(b, ft, d, iv.min, iv.ind, lt|eq) - addRestrictions(b, ft, d, iv.ind, iv.max, lt) + if iv.flags&indVarMinExc == 0 { + addRestrictions(b, ft, d, iv.min, iv.ind, lt|eq) + } else { + addRestrictions(b, ft, d, iv.min, iv.ind, lt) + } + + if iv.flags&indVarMaxInc == 0 { + addRestrictions(b, ft, d, iv.ind, iv.max, lt) + } else { + addRestrictions(b, ft, d, iv.ind, iv.max, lt|eq) + } } // addBranchRestrictions updates the factsTables ft with the facts learned when |