From: Richard Sandiford <richard.sandiford@arm.com>
Date: Wed, 21 May 2025 09:01:26 +0000 (+0100)
Subject: nds32: Avoid accessing beyond the operands[] array
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a6ec398042c6054cbf2c08b646df98b63a9418d5;p=thirdparty%2Fgcc.git

nds32: Avoid accessing beyond the operands[] array

This pattern used operands[2] to hold the shift amount, even though
the pattern doesn't have an operand 2 (not even as a match_dup).
This caused a build failure with -Werror:

  array subscript 2 is above array bounds of ‘rtx_def* [2]’

gcc/
	PR target/100837
	* config/nds32/nds32-intrinsic.md (unspec_get_pending_int): Use
	a local variable instead of operands[2].
---

diff --git a/gcc/config/nds32/nds32-intrinsic.md b/gcc/config/nds32/nds32-intrinsic.md
index e05dce105099..85acea330f07 100644
--- a/gcc/config/nds32/nds32-intrinsic.md
+++ b/gcc/config/nds32/nds32-intrinsic.md
@@ -333,30 +333,31 @@
   ""
 {
   rtx system_reg = NULL_RTX;
+  rtx shift_amt = NULL_RTX;
 
   /* Set system register form nds32_intrinsic_register_names[].  */
   if ((INTVAL (operands[1]) >= NDS32_INT_H0)
       && (INTVAL (operands[1]) <= NDS32_INT_H15))
     {
       system_reg = GEN_INT (__NDS32_REG_INT_PEND__);
-      operands[2] = GEN_INT (31 - INTVAL (operands[1]));
+      shift_amt = GEN_INT (31 - INTVAL (operands[1]));
     }
   else if (INTVAL (operands[1]) == NDS32_INT_SWI)
     {
       system_reg = GEN_INT (__NDS32_REG_INT_PEND__);
-      operands[2] = GEN_INT (15);
+      shift_amt = GEN_INT (15);
     }
   else if ((INTVAL (operands[1]) >= NDS32_INT_H16)
 	   && (INTVAL (operands[1]) <= NDS32_INT_H31))
     {
       system_reg = GEN_INT (__NDS32_REG_INT_PEND2__);
-      operands[2] = GEN_INT (31 - INTVAL (operands[1]));
+      shift_amt = GEN_INT (31 - INTVAL (operands[1]));
     }
   else if ((INTVAL (operands[1]) >= NDS32_INT_H32)
 	   && (INTVAL (operands[1]) <= NDS32_INT_H63))
     {
       system_reg = GEN_INT (__NDS32_REG_INT_PEND3__);
-      operands[2] = GEN_INT (31 - (INTVAL (operands[1]) - 32));
+      shift_amt = GEN_INT (31 - (INTVAL (operands[1]) - 32));
     }
   else
     error ("%<get_pending_int%> not support %<NDS32_INT_ALZ%>,"
@@ -366,7 +367,7 @@
   if (system_reg != NULL_RTX)
     {
       emit_insn (gen_unspec_volatile_mfsr (operands[0], system_reg));
-      emit_insn (gen_ashlsi3 (operands[0], operands[0], operands[2]));
+      emit_insn (gen_ashlsi3 (operands[0], operands[0], shift_amt));
       emit_insn (gen_lshrsi3 (operands[0], operands[0], GEN_INT (31)));
       emit_insn (gen_unspec_dsb ());
     }