From c5deaa27b0070748237f4341c3635ed05d90d8b6 Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Thu, 25 Nov 2021 11:09:50 -0500
Subject: [PATCH] Reg.Liveness: Don't repeatedly construct UniqSets
---
compiler/GHC/CmmToAsm/Reg/Liveness.hs | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/compiler/GHC/CmmToAsm/Reg/Liveness.hs b/compiler/GHC/CmmToAsm/Reg/Liveness.hs
index 90fbeb06a258..cd258e10e8c5 100644
--- a/compiler/GHC/CmmToAsm/Reg/Liveness.hs
+++ b/compiler/GHC/CmmToAsm/Reg/Liveness.hs
@@ -1024,15 +1024,15 @@ liveness1 platform liveregs blockmap (LiveInstr instr _)
= (liveregs1, LiveInstr instr
(Just $ Liveness
{ liveBorn = emptyUniqSet
- , liveDieRead = mkUniqSet r_dying
- , liveDieWrite = mkUniqSet w_dying }))
+ , liveDieRead = r_dying
+ , liveDieWrite = w_dying }))
| otherwise
= (liveregs_br, LiveInstr instr
(Just $ Liveness
{ liveBorn = emptyUniqSet
, liveDieRead = mkUniqSet r_dying_br
- , liveDieWrite = mkUniqSet w_dying }))
+ , liveDieWrite = w_dying }))
where
!(RU read written) = regUsageOfInstr platform instr
@@ -1044,10 +1044,12 @@ liveness1 platform liveregs blockmap (LiveInstr instr _)
-- registers that are not live beyond this point, are recorded
-- as dying here.
- r_dying = [ reg | reg <- read, reg `notElem` written,
+ r_dying = mkUniqSet
+ [ reg | reg <- read, reg `notElem` written,
not (elementOfUniqSet reg liveregs) ]
- w_dying = [ reg | reg <- written,
+ w_dying = mkUniqSet
+ [ reg | reg <- written,
not (elementOfUniqSet reg liveregs) ]
-- union in the live regs from all the jump destinations of this
@@ -1067,6 +1069,6 @@ liveness1 platform liveregs blockmap (LiveInstr instr _)
-- registers that are live only in the branch targets should
-- be listed as dying here.
live_branch_only = live_from_branch `minusUniqSet` liveregs
- r_dying_br = nonDetEltsUniqSet (mkUniqSet r_dying `unionUniqSets`
+ r_dying_br = nonDetEltsUniqSet (r_dying `unionUniqSets`
live_branch_only)
-- See Note [Unique Determinism and code generation]
--
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