There is a bug with the RNG intrinsics in their return code. The definition says:
"Stores a 64-bit random number into the object pointed to by the argument and returns zero.
If the implementation could not generate a random number within a reasonable period of time
the object pointed to by the input is set to zero and a non-zero value is returned."
This means we should be testing whether to return non-zero with:
CSET W0, EQ
rather than NE.
This patch fixes that.
gcc/ChangeLog:
* config/aarch64/aarch64-builtins.c (aarch64_expand_rng_builtin): Use EQ
to compare against CC_REG rather than NE.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/acle/rng_2.c: New test.
return target;
rtx cc_reg = gen_rtx_REG (CC_Zmode, CC_REGNUM);
- rtx cmp_rtx = gen_rtx_fmt_ee (NE, SImode, cc_reg, const0_rtx);
+ rtx cmp_rtx = gen_rtx_fmt_ee (EQ, SImode, cc_reg, const0_rtx);
emit_insn (gen_aarch64_cstoresi (target, cmp_rtx, cc_reg));
return target;
}
--- /dev/null
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=armv8.5-a+rng" } */
+
+#include <arm_acle.h>
+
+int test_rndr (uint64_t *addr)
+{
+ return __rndr (addr);
+}
+
+/* { dg-final { scan-assembler-times {cset\t...?, eq} 1 } } */
+