diff mbox series

[Ada] Fix biased integer arithmetic

Message ID 2955409.SQpzPzQ6z4@fomalhaut
State New
Headers show
Series [Ada] Fix biased integer arithmetic | expand

Commit Message

Eric Botcazou Nov. 11, 2020, 2:13 p.m. UTC 
The Ada compiler uses a biased representation when a size clause reserves 
fewer bits than normal either for the lower or for the upper bound.

Tested on x86-64/Linux, applied on the mainline, 10 and 9 branches.


2020-11-11  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/trans.c (build_binary_op_trapv): Convert operands
	to the result type before doing generic overflow checking.


2020-11-11  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/bias2.adb: New test.
diff mbox series

Patch

diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
index 065fcd2f956..7be8463d32b 100644
--- a/gcc/ada/gcc-interface/trans.c
+++ b/gcc/ada/gcc-interface/trans.c
@@ -9361,6 +9361,11 @@  build_binary_op_trapv (enum tree_code code, tree gnu_type, tree left,
   /* If no operand is a constant, we use the generic implementation.  */
   if (TREE_CODE (lhs) != INTEGER_CST && TREE_CODE (rhs) != INTEGER_CST)
     {
+      /* First convert the operands to the result type like build_binary_op.
+	 This is where the bias is made explicit for biased types.  */
+      lhs = convert (gnu_type, lhs);
+      rhs = convert (gnu_type, rhs);
+
       /* Never inline a 64-bit mult for a 32-bit target, it's way too long.  */
       if (code == MULT_EXPR && precision == 64 && BITS_PER_WORD < 64)
 	{