[Valgrind-developers] [valgrind] iropt regtest: use mrand32() instead of rand()

[Paul F. <pa...@so...>]

https://sourceware.org/cgit/valgrind/commit/?id=c322bf33df88d1e8813434f7beeba909831a6a79

commit c322bf33df88d1e8813434f7beeba909831a6a79
Author: Paul Floyd <pj...@wa...>
Date:   Thu Jul 17 20:38:54 2025 +0200

    iropt regtest: use mrand32() instead of rand()
    
    On illumos rand() has a RAND_MAX of 32k only. That's not enough to
    generate 64bit values easily. So use mrand48() which genrerates
    the full range of 32bit int values.

Diff:
---
 none/tests/iropt-test/main.c | 2 +-
 none/tests/iropt-test/util.c | 9 +++------
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/none/tests/iropt-test/main.c b/none/tests/iropt-test/main.c
index 2622515e55..9f1cc5083a 100644
--- a/none/tests/iropt-test/main.c
+++ b/none/tests/iropt-test/main.c
@@ -45,7 +45,7 @@ int
 main(int argc, char *argv[])
 {
    assert(sizeof(long long) == 8);
-   assert(RAND_MAX == INT32_MAX);
+   srand48(42L);
 
    for (int i = 1; i < argc; ++i) {
       if (strcmp(argv[i], "-v") == 0)
diff --git a/none/tests/iropt-test/util.c b/none/tests/iropt-test/util.c
index 072ff90c36..18b671114c 100644
--- a/none/tests/iropt-test/util.c
+++ b/none/tests/iropt-test/util.c
@@ -109,7 +109,7 @@ bitsof_irtype(IRType ty)
 uint64_t
 get_random_value(IRType type)
 {
-   uint64_t val = rand();
+   uint64_t val = mrand48();
 
    switch (type) {
    case Ity_I1:  return val & 0x1;
@@ -117,11 +117,8 @@ get_random_value(IRType type)
    case Ity_I16: return val & UINT16_MAX;
    case Ity_I32: return val & UINT32_MAX;
    case Ity_I64:
-      /* Note, that RAND_MAX == INT32_MAX. Therefore, simply concatenating
-         two rand() values would never produce a value with MSB == 1 */
-      val <<= (32 + 1);
-      val |= rand() << 1;
-      val |= rand() & 0x1;
+      val <<= 32;
+      val |= mrand48();
       return val;
 
    default: