34 lines
1.3 KiB
Diff
34 lines
1.3 KiB
Diff
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commit fb6a77ed78876083e8ba4c2f92384db5c2e41be8
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Author: Mark Wielaard <mark@klomp.org>
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Date: Tue Feb 8 16:36:08 2022 +0100
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ppc64 --track-origins=yes failure because of bad cmov addHRegUse
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For Pin_CMov getRegUsage_PPCInstr called addHRegUse for the dst
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register with HRmWrite, but since this is a conditional move the
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register could be both read and written (read + write = modify).
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This matches the dst of Pin_FpCMov and Pin_AvCMov.
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In a very rare case, and only with --track-origins=yes, this
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could cause bad code generation.
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This is slightly amazing, this code is from 2005 and as far as
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I know we never seen an issue with --track-origins=yes on power
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before. And I have been unable to come up simple reproducer.
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https://bugs.kde.org/show_bug.cgi?id=449672
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diff --git a/VEX/priv/host_ppc_defs.c b/VEX/priv/host_ppc_defs.c
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index 3ae0f6e08..4222b4786 100644
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--- a/VEX/priv/host_ppc_defs.c
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+++ b/VEX/priv/host_ppc_defs.c
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@@ -2590,7 +2590,7 @@ void getRegUsage_PPCInstr ( HRegUsage* u, const PPCInstr* i, Bool mode64 )
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return;
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case Pin_CMov:
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addRegUsage_PPCRI(u, i->Pin.CMov.src);
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- addHRegUse(u, HRmWrite, i->Pin.CMov.dst);
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+ addHRegUse(u, HRmModify, i->Pin.CMov.dst);
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return;
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case Pin_Load:
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addRegUsage_PPCAMode(u, i->Pin.Load.src);
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