From: Andrew Burgess <aburgess@redhat.com>
To: gdb-patches@sourceware.org
Subject: [PATCH 05/10] sim/ppc: fix for operator precedence warning from clang
Date: Wed, 19 Oct 2022 16:24:44 +0100 [thread overview]
Message-ID: <bad971a3bda505005d02a880cd1b6c9eca87d47e.1666192979.git.aburgess@redhat.com> (raw)
In-Reply-To: <cover.1666192979.git.aburgess@redhat.com>
In the ppc simulator, clang was warning about some code like this:
busy_ptr->nr_writebacks = 1 + (PPC_ONE_BIT_SET_P(out_vmask)) ? 1 : 2;
The warning was:
operator '?:' has lower precedence than '+'; '+' will be evaluated first
I suspect that this is not the original authors intention.
PPC_ONE_BIT_SET_P is going to be 0 or 1, so if we evaluate the '+'
first, the condition will always be non-zero, so true. The whole
expression could then be simplified to just '1', which doesn't make
much sense.
I suspect the answer the author was expecting was either 2 or 3. Why
they didn't just write:
busy_ptr->nr_writebacks = (PPC_ONE_BIT_SET_P(out_vmask)) ? 2 : 3;
I have no clue, however, to keep the structure of the code unchanged,
I've updated things to:
busy_ptr->nr_writebacks = 1 + ((PPC_ONE_BIT_SET_P(out_vmask)) ? 1 : 2);
which silences the warning from clang, and is, I am guessing, what the
original author intended.
---
sim/ppc/altivec.igen | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sim/ppc/altivec.igen b/sim/ppc/altivec.igen
index 63fe95a53d5..e7962027bd6 100644
--- a/sim/ppc/altivec.igen
+++ b/sim/ppc/altivec.igen
@@ -231,7 +231,7 @@ void::model-function::ppc_insn_vr_vscr:itable_index index, model_data *model_ptr
busy_ptr->vscr_busy = 1;
if (out_vmask)
- busy_ptr->nr_writebacks = 1 + (PPC_ONE_BIT_SET_P(out_vmask)) ? 1 : 2;
+ busy_ptr->nr_writebacks = 1 + ((PPC_ONE_BIT_SET_P(out_vmask)) ? 1 : 2);
if (WITH_TRACE && ppc_trace[trace_model])
model_trace_altivec_make_busy(model_ptr, vr_mask, 0);
--
2.25.4
next prev parent reply other threads:[~2022-10-19 15:25 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-19 15:24 [PATCH 00/10] Building the sim/ tree with clang Andrew Burgess
2022-10-19 15:24 ` [PATCH 01/10] sim/sh: use fabs instead of abs Andrew Burgess
2022-10-23 13:53 ` Mike Frysinger
2022-10-24 16:05 ` Andrew Burgess
2022-10-19 15:24 ` [PATCH 02/10] sim/ppc: don't try to print an uninitialized variable Andrew Burgess
2022-10-23 13:51 ` Mike Frysinger
2022-10-24 16:05 ` Andrew Burgess
2022-10-19 15:24 ` [PATCH 03/10] sim/ppc: initialize a memory buffer in all cases Andrew Burgess
2022-10-23 13:50 ` Mike Frysinger
2022-10-24 16:25 ` Andrew Burgess
2022-10-19 15:24 ` [PATCH 04/10] sim/ppc: don't pass uninitialized value to semctl for GETVAL calls Andrew Burgess
2022-10-23 14:01 ` Mike Frysinger
2022-10-19 15:24 ` Andrew Burgess [this message]
2022-10-23 13:55 ` [PATCH 05/10] sim/ppc: fix for operator precedence warning from clang Mike Frysinger
2022-10-24 16:26 ` Andrew Burgess
2022-10-19 15:24 ` [PATCH 06/10] sim/aarch64: remove two unused functions Andrew Burgess
2022-10-23 13:55 ` Mike Frysinger
2022-10-24 16:26 ` Andrew Burgess
2022-10-19 15:24 ` [PATCH 07/10] sim/rx: delete an unused function Andrew Burgess
2022-10-23 13:54 ` Mike Frysinger
2022-10-19 15:24 ` [PATCH 08/10] sim/h8300: avoid self assignment Andrew Burgess
2022-10-23 13:52 ` Mike Frysinger
2022-10-24 16:26 ` Andrew Burgess
2022-10-19 15:24 ` [PATCH 09/10] sim/lm32: fix some missing function declaration warnings Andrew Burgess
2022-10-23 14:13 ` Mike Frysinger
2022-10-24 16:27 ` Andrew Burgess
2022-10-19 15:24 ` [PATCH 10/10] sim/cris/m32c/sh: disable use of -Werror Andrew Burgess
2022-10-20 3:53 ` Tsukasa OI
2022-10-21 15:58 ` Andrew Burgess
2022-10-24 8:58 ` Tsukasa OI
2022-10-24 16:23 ` Andrew Burgess
2022-10-20 18:36 ` Tom Tromey
2022-10-23 14:17 ` Mike Frysinger
2022-10-20 18:36 ` [PATCH 00/10] Building the sim/ tree with clang Tom Tromey
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