LoongArch: Fix runtime error in a gcc build with --with-build-config=bootstrap-ubsan

gcc/ChangeLog:

	* config/loongarch/loongarch.cc (loongarch_split_plus_constant):
	avoid left shift of negative value -0x8000.

diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index c95fc83362e9b7a34b5e3eb28c6c356724b3b520..d3896d72bc2edc5fadfc8b1f4284c275fbe73865 100644 (file)
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -4269,7 +4269,7 @@ loongarch_split_plus_constant (rtx *op, machine_mode mode)
   else if (loongarch_addu16i_imm12_operand_p (v, mode))
     a = (v & ~HWIT_UC_0xFFF) + ((v & 0x800) << 1);
   else if (mode == DImode && DUAL_ADDU16I_OPERAND (v))
-    a = (v > 0 ? 0x7fff : -0x8000) << 16;
+    a = (v > 0 ? 0x7fff0000 : ~0x7fffffff);
   else
     gcc_unreachable ();