[PATCH] ipa: Force args obtined through pass-through maps to the expected type (PR 113964)

[Martin Jambor]

Hi,

interactions of IPA-CP and IPA-SRA on the same data is a rather big
source of issues, I'm afraid.  PR 113964 is a situation where IPA-CP
propagates an unsigned short in a union parameter into a function
which itself calls a different function which has a same union
parameter and both these union parameters are split with IPA-SRA.  The
leaf function however uses a signed short member of the union.

In the calling function, we get the unsigned constant as the
replacement for the union and it is then passed in the call without
any type compatibility checks.  Apparently on riscv64 it matters
whether the parameter is signed or unsigned short and so the leaf
function can see different values.

Fixed by using useless_type_conversion_p at the appropriate place and
if it fails, use force_value_to type as elsewhere in similar
situations.

Bootstrapped and tested on x86_64-linux, the reporter has also run the
testsuite with this patch on riscv64 and reported in Bugzilla there were
no issues.

OK for master and GCC 13?

Thanks,

Martin


gcc/ChangeLog:

2024-04-04  Martin Jambor  <mjam...@suse.cz>

        PR ipa/113964
        * ipa-param-manipulation.cc (ipa_param_adjustments::modify_call):
        Force values obtined through pass-through maps to the expected
        split type.

gcc/testsuite/ChangeLog:

2024-04-04  Patrick O'Neill  <patr...@rivosinc.com>
            Martin Jambor  <mjam...@suse.cz>

        PR ipa/113964
        * gcc.dg/ipa/pr114247.c: New test.
---
 gcc/ipa-param-manipulation.cc       |  6 ++++++
 gcc/testsuite/gcc.dg/ipa/pr114247.c | 31 +++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 gcc/testsuite/gcc.dg/ipa/pr114247.c

diff --git a/gcc/ipa-param-manipulation.cc b/gcc/ipa-param-manipulation.cc
index 3e0df6a6f77..b4ca78b652e 100644
--- a/gcc/ipa-param-manipulation.cc
+++ b/gcc/ipa-param-manipulation.cc
@@ -740,6 +740,12 @@ ipa_param_adjustments::modify_call (cgraph_edge *cs,
          }
       if (repl)
        {
+         if (!useless_type_conversion_p(apm->type, repl->typed.type))
+           {
+             repl = force_value_to_type (apm->type, repl);
+             repl = force_gimple_operand_gsi (&gsi, repl,
+                                              true, NULL, true, GSI_SAME_STMT);
+           }
          vargs.quick_push (repl);
          continue;
        }
diff --git a/gcc/testsuite/gcc.dg/ipa/pr114247.c 
b/gcc/testsuite/gcc.dg/ipa/pr114247.c
new file mode 100644
index 00000000000..60aa2bc0122
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/pr114247.c
@@ -0,0 +1,31 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fsigned-char -fno-strict-aliasing -fwrapv" } */
+
+union a {
+  unsigned short b;
+  int c;
+  signed short d;
+};
+int e, f = 1, g;
+long h;
+const int **i;
+void j(union a k, int l, unsigned m) {
+  const int *a[100];
+  i = &a[0];
+  h = k.d;
+}
+static int o(union a k) {
+  k.d = -1;
+  while (1)
+    if (f)
+      break;
+  j(k, g, e);
+  return 0;
+}
+int main() {
+  union a n = {1};
+  o(n);
+  if (h != -1)
+    __builtin_abort();
+  return 0;
+}
-- 
2.44.0