[PATCH] lower-bitint: Don't use m_loads for loads used in GIMPLE_ASM [PR113464]

[Jakub Jelinek]

Hi!

Like for GIMPLE_PHIs or calls, even for GIMPLE_ASMs we want
a corresponding VAR_DECL assigned for lhs SSA_NAMEs of loads
from memory, as even GIMPLE_ASM relies on those VAR_DECLs to exist.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2024-01-19  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/113464
        * gimple-lower-bitint.cc (gimple_lower_bitint): Don't try to
        optimize loads into GIMPLE_ASM stmts.

        * gcc.dg/bitint-75.c: New test.

--- gcc/gimple-lower-bitint.cc.jj       2024-01-18 08:44:08.337270271 +0100
+++ gcc/gimple-lower-bitint.cc  2024-01-18 19:57:11.791976322 +0100
@@ -6249,7 +6249,8 @@ gimple_lower_bitint (void)
                  if (is_gimple_debug (use_stmt))
                    continue;
                  if (gimple_code (use_stmt) == GIMPLE_PHI
-                     || is_gimple_call (use_stmt))
+                     || is_gimple_call (use_stmt)
+                     || gimple_code (use_stmt) == GIMPLE_ASM)
                    {
                      optimizable_load = false;
                      break;
--- gcc/testsuite/gcc.dg/bitint-75.c.jj 2024-01-18 20:08:21.710557536 +0100
+++ gcc/testsuite/gcc.dg/bitint-75.c    2024-01-18 20:07:18.017447734 +0100
@@ -0,0 +1,11 @@
+/* PR tree-optimization/113464 */
+/* { dg-do compile { target bitint65535 } } */
+/* { dg-options "-O2 -w -std=gnu23" } */
+
+_BitInt(65532) i;
+
+void
+foo (void)
+{
+  __asm__ ("" : "+r" (i));     /* { dg-error "impossible constraint" } */
+}

        Jakub