diff options
Diffstat (limited to 'compiler/GHC/Core/Rules.hs')
| -rw-r--r-- | compiler/GHC/Core/Rules.hs | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/compiler/GHC/Core/Rules.hs b/compiler/GHC/Core/Rules.hs index 668f273a1f..55a099efbd 100644 --- a/compiler/GHC/Core/Rules.hs +++ b/compiler/GHC/Core/Rules.hs @@ -714,11 +714,15 @@ match :: RuleMatchEnv -> CoreExpr -- Target -> Maybe RuleSubst --- We look through certain ticks. See note [Tick annotations in RULE matching] +-- We look through certain ticks. See Note [Tick annotations in RULE matching] match renv subst e1 (Tick t e2) | tickishFloatable t = match renv subst' e1 e2 where subst' = subst { rs_binds = rs_binds subst . mkTick t } +match renv subst (Tick t e1) e2 + -- Ignore ticks in rule template. + | tickishFloatable t + = match renv subst e1 e2 match _ _ e@Tick{} _ = pprPanic "Tick in rule" (ppr e) @@ -1016,7 +1020,7 @@ Hence, (a) the guard (not (isLocallyBoundR v2)) Note [Tick annotations in RULE matching] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -We used to unconditionally look through Notes in both template and +We used to unconditionally look through ticks in both template and expression being matched. This is actually illegal for counting or cost-centre-scoped ticks, because we have no place to put them without changing entry counts and/or costs. So now we just fail the match in @@ -1025,6 +1029,11 @@ these cases. On the other hand, where we are allowed to insert new cost into the tick scope, we can float them upwards to the rule application site. +Moreover, we may encounter ticks in the template of a rule. There are a few +ways in which these may be introduced (e.g. #18162, #17619). Such ticks are +ignored by the matcher. See Note [Simplifying rules] in +GHC.Core.Opt.Simplify.Utils for details. + cf Note [Notes in call patterns] in GHC.Core.Opt.SpecConstr Note [Matching lets] |