diff options
Diffstat (limited to 'compiler/codeGen')
| -rw-r--r-- | compiler/codeGen/StgCmmUtils.hs | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/compiler/codeGen/StgCmmUtils.hs b/compiler/codeGen/StgCmmUtils.hs index 763177f297..98295c9836 100644 --- a/compiler/codeGen/StgCmmUtils.hs +++ b/compiler/codeGen/StgCmmUtils.hs @@ -626,14 +626,18 @@ mk_switch tag_expr branches mb_deflt lo_tag hi_tag via_C -- lo_tag <= mid_tag < hi_tag -- lo_branches have tags < mid_tag -- hi_branches have tags >= mid_tag + (lo_branches, mid_tag, hi_branches) = divideBranches branches - (mid_tag,_) = branches !! (n_branches `div` 2) - -- 2 branches => n_branches `div` 2 = 1 - -- => branches !! 1 give the *second* tag - -- There are always at least 2 branches here +divideBranches :: Ord a => [(a,b)] -> ([(a,b)], a, [(a,b)]) +divideBranches branches = (lo_branches, mid, hi_branches) + where + -- 2 branches => n_branches `div` 2 = 1 + -- => branches !! 1 give the *second* tag + -- There are always at least 2 branches here + (mid,_) = branches !! (length branches `div` 2) (lo_branches, hi_branches) = span is_lo branches - is_lo (t,_) = t < mid_tag + is_lo (t,_) = t < mid -------------- emitCmmLitSwitch :: CmmExpr -- Tag to switch on @@ -681,7 +685,7 @@ mk_lit_switch scrut deflt bounds [(lit,blk)] where -- If the bounds already imply scrut == lit, then we can skip the final check (#10129) l `onlyWithinBounds'` (Just lo, Just hi) = l `onlyWithinBounds` (lo, hi) - l `onlyWithinBounds'` _ = False + _ `onlyWithinBounds'` _ = False mk_lit_switch scrut deflt_blk_id (lo_bound, hi_bound) branches = do dflags <- getDynFlags @@ -689,12 +693,7 @@ mk_lit_switch scrut deflt_blk_id (lo_bound, hi_bound) branches hi_blk <- mk_lit_switch scrut deflt_blk_id bounds_hi hi_branches mkCmmIfThenElse (cond dflags) lo_blk hi_blk where - n_branches = length branches - (mid_lit,_) = branches !! (n_branches `div` 2) - -- See notes above re mid_tag - - (lo_branches, hi_branches) = span is_lo branches - is_lo (t,_) = t < mid_lit + (lo_branches, mid_lit, hi_branches) = divideBranches branches bounds_lo = (lo_bound, Just mid_lit) bounds_hi = (Just mid_lit, hi_bound) |