44 lines
1.4 KiB
Diff
44 lines
1.4 KiB
Diff
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From 15f1e94ddd7128f407ada43fd9e4b26d4a8bba8d Mon Sep 17 00:00:00 2001
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From: Xi Ruoyao <xry111@xry111.site>
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Date: Fri, 4 Nov 2022 01:35:25 +0800
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Subject: [PATCH 026/124] LoongArch: fix signed overflow in
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loongarch_emit_int_compare
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Signed overflow is an undefined behavior, so we need to prevent it from
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happening, instead of "checking" the result.
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gcc/ChangeLog:
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* config/loongarch/loongarch.cc (loongarch_emit_int_compare):
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Avoid signed overflow.
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Signed-off-by: Peng Fan <fanpeng@loongson.cn>
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Signed-off-by: ticat_fp <fanpeng@loongson.cn>
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---
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gcc/config/loongarch/loongarch.cc | 7 +++++--
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1 file changed, 5 insertions(+), 2 deletions(-)
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diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
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index e9ba3374e..d552b162a 100644
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--- a/gcc/config/loongarch/loongarch.cc
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+++ b/gcc/config/loongarch/loongarch.cc
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@@ -4177,10 +4177,13 @@ loongarch_emit_int_compare (enum rtx_code *code, rtx *op0, rtx *op1)
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if (!increment && !decrement)
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continue;
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+ if ((increment && rhs == HOST_WIDE_INT_MAX)
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+ || (decrement && rhs == HOST_WIDE_INT_MIN))
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+ break;
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+
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new_rhs = rhs + (increment ? 1 : -1);
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if (loongarch_integer_cost (new_rhs)
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- < loongarch_integer_cost (rhs)
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- && (rhs < 0) == (new_rhs < 0))
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+ < loongarch_integer_cost (rhs))
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{
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*op1 = GEN_INT (new_rhs);
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*code = mag_comparisons[i][increment];
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--
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2.33.0
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