File _service:tar_scm_kernel_repo:0043-LoongArch-fix... of Package gcc

File _service:tar_scm_kernel_repo:0043-LoongArch-fix-signed-overflow-in-loongarch_emit_int_.patch of Package gcc

From cbebeb6af741b628e9714240fdcebca58c61e56e Mon Sep 17 00:00:00 2001
From: XingLi <lixing@loongson.cn>
Date: Thu, 27 Jul 2023 09:16:55 +0800
Subject: [PATCH 2/2]  LoongArch: fix signed overflow in
 loongarch_emit_int_compare

Signed overflow is an undefined behavior, so we need to prevent it from
happening, instead of "checking" the result.

gcc/ChangeLog:

* config/loongarch/loongarch.cc (loongarch_emit_int_compare):
        Avoid signed overflow.
From: Xi Ruoyao <xry111@xry111.site>
---
 gcc/config/loongarch/loongarch.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/gcc/config/loongarch/loongarch.c b/gcc/config/loongarch/loongarch.c
index 4ddcaa446..95b4ed5d9 100644
--- a/gcc/config/loongarch/loongarch.c
+++ b/gcc/config/loongarch/loongarch.c
@@ -4174,10 +4174,13 @@ loongarch_emit_int_compare (enum rtx_code *code, rtx *op0, rtx *op1)
 	      if (!increment && !decrement)
 		continue;
 
+	      if ((increment && rhs == HOST_WIDE_INT_MAX)
+		  || (decrement && rhs == HOST_WIDE_INT_MIN))
+		break;
+
 	      new_rhs = rhs + (increment ? 1 : -1);
 	      if (loongarch_integer_cost (new_rhs)
-		    < loongarch_integer_cost (rhs)
-		  && (rhs < 0) == (new_rhs < 0))
+		    < loongarch_integer_cost (rhs))
 		{
 		  *op1 = GEN_INT (new_rhs);
 		  *code = mag_comparisons[i][increment];
-- 
2.27.0