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Diffstat (limited to 'compiler/cmm/CmmSink.hs')
| -rw-r--r-- | compiler/cmm/CmmSink.hs | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/compiler/cmm/CmmSink.hs b/compiler/cmm/CmmSink.hs index 02195c91e1..80c6eed349 100644 --- a/compiler/cmm/CmmSink.hs +++ b/compiler/cmm/CmmSink.hs @@ -205,7 +205,12 @@ walk nodes assigs = go nodes emptyBlock assigs -- to get all the dead code, but it catches the common case of -- superfluous reloads from the stack that the stack allocator -- leaves behind. + -- + -- Also we catch "r = r" here. You might think it would fall + -- out of inlining, but the inliner will see that r is live + -- after the instruction and choose not to inline r in the rhs. discard = case node of + CmmAssign r (CmmReg r') | r == r' -> True CmmAssign (CmmLocal r) _ -> not (r `Set.member` live) _otherwise -> False |