From: Mike Frysinger <vapier@gentoo.org>
Date: Fri, 12 Nov 2021 00:30:41 +0000 (-0500)
Subject: sim: sh: rework carry checks to not rely on integer overflows
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=dc5a4621600e650b89deb92c79eaacc73fcc767a;p=binutils-gdb.git

sim: sh: rework carry checks to not rely on integer overflows

In <=gcc-7 versions, -fstrict-overflow is enabled by default, and that
triggers warnings in this code that relies on integer overflows to test
for carries.  Change the logic to test against the limit directly.
---

diff --git a/sim/sh/gencode.c b/sim/sh/gencode.c
index 80eecfdf1d3..5eb7caf2589 100644
--- a/sim/sh/gencode.c
+++ b/sim/sh/gencode.c
@@ -2266,7 +2266,7 @@ op ppi_tab[] =
     "int Sx_grd = GET_DSP_GRD (x);",
     "",
     "res = Sx - 0x10000;",
-    "carry = res > Sx;",
+    "carry = Sx < (INT_MIN + 0x10000);",
     "res_grd = Sx_grd - carry;",
     "COMPUTE_OVERFLOW;",
     "ADD_SUB_GE;",
@@ -2277,7 +2277,7 @@ op ppi_tab[] =
     "int Sx_grd = GET_DSP_GRD (x);",
     "",
     "res = Sx + 0x10000;",
-    "carry = res < Sx;",
+    "carry = Sx > (INT_MAX - 0x10000);",
     "res_grd = Sx_grd + carry;",
     "COMPUTE_OVERFLOW;",
     "ADD_SUB_GE;",
@@ -2288,7 +2288,7 @@ op ppi_tab[] =
     "int Sy_grd = SIGN32 (Sy);",
     "",
     "res = Sy - 0x10000;",
-    "carry = res > Sy;",
+    "carry = Sy < (INT_MIN + 0x10000);",
     "res_grd = Sy_grd - carry;",
     "COMPUTE_OVERFLOW;",
     "ADD_SUB_GE;",
@@ -2299,7 +2299,7 @@ op ppi_tab[] =
     "int Sy_grd = SIGN32 (Sy);",
     "",
     "res = Sy + 0x10000;",
-    "carry = res < Sy;",
+    "carry = Sy > (INT_MAX - 0x10000);",
     "res_grd = Sy_grd + carry;",
     "COMPUTE_OVERFLOW;",
     "ADD_SUB_GE;",