[gcc r14-9492] expand: EXTEND_BITINT CALL_EXPR results [PR114332]

[gcc r14-9492] expand: EXTEND_BITINT CALL_EXPR results [PR114332]

[Jakub Jelinek]

https://gcc.gnu.org/g:0319f265eddd17c32cb037b71489d9882a6eb00d

commit r14-9492-g0319f265eddd17c32cb037b71489d9882a6eb00d
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Mar 15 10:10:57 2024 +0100

    expand: EXTEND_BITINT CALL_EXPR results [PR114332]
    
    The x86-64 and aarch64 psABIs (and the unwritten ia64 psABI part) say that
    the padding bits of _BitInt are undefined, while the expansion internally
    typically assumes that non-mode precision integers are sign/zero extended
    and extends after operations.  We handle that mismatch with EXTEND_BITINT
    done when reading from untrusted sources like function arguments, reading
    _BitInt from memory etc. but otherwise keep relying on stuff being extended
    internally (say in pseudos).
    The return value of a function is an ABI boundary though too and we need
    to extend that too.
    
    2024-03-15  Jakub Jelinek  <jakub@redhat.com>
    
            PR middle-end/114332
            * expr.cc (expand_expr_real_1): EXTEND_BITINT also CALL_EXPR results.

Diff:
---
 gcc/expr.cc                              |  3 ++-
 gcc/testsuite/gcc.dg/torture/bitint-64.c | 22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/gcc/expr.cc b/gcc/expr.cc
index f7d74525c15..2918c469735 100644
--- a/gcc/expr.cc
+++ b/gcc/expr.cc
@@ -12350,7 +12350,8 @@ expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
 	    return expand_builtin (exp, target, subtarget, tmode, ignore);
 	  }
       }
-      return expand_call (exp, target, ignore);
+      temp = expand_call (exp, target, ignore);
+      return EXTEND_BITINT (temp);
 
     case VIEW_CONVERT_EXPR:
       op0 = NULL_RTX;
diff --git a/gcc/testsuite/gcc.dg/torture/bitint-64.c b/gcc/testsuite/gcc.dg/torture/bitint-64.c
new file mode 100644
index 00000000000..8f0f21cbee2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/bitint-64.c
@@ -0,0 +1,22 @@
+/* PR middle-end/114332 */
+/* { dg-do run { target bitint } } */
+/* { dg-options "-std=c23 -fwrapv" } */
+/* { dg-skip-if "" { ! run_expensive_tests }  { "*" } { "-O0" "-O2" } } */
+/* { dg-skip-if "" { ! run_expensive_tests } { "-flto" } { "" } } */
+
+enum E { E22 = 22 } e = E22;
+
+_BitInt (5)
+foo (void)
+{
+  _Atomic _BitInt (5) b = 0;
+  b += e;
+  return b;
+}
+
+int
+main ()
+{
+  if (foo () != -10)
+    __builtin_abort ();
+}