tailc: Handle other forms of finally_tmp.N conditional cleanups after musttail [PR121389]

My earlier r16-1886 PR120608 change incorrectly assumed that the
finally_tmp.N vars introduced by eh pass will be only initialized
to values 0 and 1 and there will be only EQ_EXPR/NE_EXPR comparisons
of those.

The following testcases show that is a bad assumption, the eh pass
sets finally_tmp.N vars to 0 up to some highest index depending on
hoiw many different exits there are from the finally region.
And it emits then switch (finally_tmp.N) statement for all the
different cases.  So, if it uses more than 0/1 indexes, the lowering
of the switch can turn it into a series of GIMPLE_CONDs,
  if (finally_tmp.N_M > 15)
    goto ...
  else
    goto ...

  if (finally_tmp.N_M > 7)
    goto ...
  else
    goto ...
etc. (and that also means no longer single uses).  And if unlucky,
we can see a non-lowered GIMPLE_SWITCH as well.

So, the following patch removes the assumption that it has to be 0/1
and EQ_EXPR/NE_EXPR, allows all the normal integral comparisons
and handles GIMPLE_SWITCH too.

2025-08-08  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/121389
	* tree-tailcall.cc (find_tail_calls): For finally_tmp.N
	handle not just GIMPLE_CONDs with EQ_EXPR/NE_EXPR and only
	values 0 and 1, but arbitrary non-negative values, arbitrary
	comparisons in conditions and also GIMPLE_SWITCH next to
	GIMPLE_CONDs.

	* c-c++-common/asan/pr121389-1.c: New test.
	* c-c++-common/asan/pr121389-2.c: New test.
	* c-c++-common/asan/pr121389-3.c: New test.
	* c-c++-common/asan/pr121389-4.c: New test.

4 files changed, 196 insertions, 0 deletions

diff --git a/gcc/testsuite/c-c++-common/asan/pr121389-1.c b/gcc/testsuite/c-c++-common/asan/pr121389-1.c
new file mode 100644
index 0000000..0116d7a
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/asan/pr121389-1.c
@@ -0,0 +1,23 @@
+// PR middle-end/121389
+// { dg-do compile { target musttail } }
+// { dg-options "-fsanitize=address" }
+
+int foo (void);
+int bar (void);
+int baz (unsigned *);
+
+int
+bar (void)
+{
+  do
+    {
+      unsigned t;
+      int u = baz (&t);
+      if (u == 42)
+	[[gnu::musttail]] return foo ();
+      if (u == -42)
+	break;
+    }
+  while (1);
+  return 42;
+}
diff --git a/gcc/testsuite/c-c++-common/asan/pr121389-2.c b/gcc/testsuite/c-c++-common/asan/pr121389-2.c
new file mode 100644
index 0000000..02914f8
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/asan/pr121389-2.c
@@ -0,0 +1,37 @@
+// PR middle-end/121389
+// { dg-do compile { target musttail } }
+// { dg-options "-fsanitize=address" }
+
+int foo (void);
+int bar (void);
+int baz (unsigned *);
+
+int
+bar (void)
+{
+  for (int a = 0; a < 420; ++a)
+    {
+      for (int b = 0; b < 420; ++b)
+	{
+	  for (int c = 0; c < 420; ++c)
+	    {
+	      unsigned t;
+	      int u = baz (&t);
+	      if (u == 42)
+		[[gnu::musttail]] return foo ();
+	      if (u == -42)
+		break;
+	      if (u == 16)
+		goto l1;
+	      if (u == 18)
+		goto l2;
+	      if (u == 20)
+		goto l3;
+	    }
+	  l3:;
+	}
+      l2:;
+    }
+  l1:;
+  return 42;
+}
diff --git a/gcc/testsuite/c-c++-common/asan/pr121389-3.c b/gcc/testsuite/c-c++-common/asan/pr121389-3.c
new file mode 100644
index 0000000..5f71e06
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/asan/pr121389-3.c
@@ -0,0 +1,130 @@
+// PR middle-end/121389
+// { dg-do compile { target musttail } }
+// { dg-options "-fsanitize=address" }
+
+int foo (void);
+int bar (void);
+int baz (unsigned *);
+
+int
+bar (void)
+{
+  for (int a = 0; a < 420; ++a)
+    {
+      for (int b = 0; b < 420; ++b)
+	{
+	  for (int c = 0; c < 420; ++c)
+	    {
+	      unsigned t;
+	      int u = baz (&t);
+	      if (u == 42)
+		[[gnu::musttail]] return foo ();
+	      if (u == -42)
+		break;
+	      if (u == 16)
+		goto l1;
+	      if (u == 18)
+		goto l2;
+	      if (u == 20)
+		goto l3;
+	      switch (u)
+		{
+		case 100: goto l100;
+		case 101: goto l101;
+		case 102: goto l102;
+		case 103: goto l103;
+		case 104: goto l104;
+		case 105: goto l105;
+		case 106: goto l106;
+		case 107: goto l107;
+		case 108: goto l108;
+		case 109: goto l109;
+		case 110: goto l110;
+		case 111: goto l111;
+		case 112: goto l112;
+		case 113: goto l113;
+		case 114: goto l114;
+		case 115: goto l115;
+		case 116: goto l116;
+		case 117: goto l117;
+		case 118: goto l118;
+		case 119: goto l119;
+		case 120: goto l120;
+		case 121: goto l121;
+		case 122: goto l122;
+		case 123: goto l123;
+		case 124: goto l124;
+		case 125: goto l125;
+		case 126: goto l126;
+		case 127: goto l127;
+		case 128: goto l128;
+		case 129: goto l129;
+		}
+	    }
+	  l3:;
+	  foo ();
+	  l100:
+	  foo ();
+	  l101:
+	  foo ();
+	  l102:
+	  foo ();
+	  l103:
+	  foo ();
+	  l104:
+	  foo ();
+	  l105:
+	  foo ();
+	  l106:
+	  foo ();
+	  l107:
+	  foo ();
+	  l108:
+	  foo ();
+	  l109:;
+	}
+      l2:;
+      foo ();
+      l110:
+      foo ();
+      l111:
+      foo ();
+      l112:
+      foo ();
+      l113:
+      foo ();
+      l114:
+      foo ();
+      l115:
+      foo ();
+      l116:
+      foo ();
+      l117:
+      foo ();
+      l118:
+      foo ();
+      l119:;
+    }
+  l1:;
+  foo ();
+  l120:
+  foo ();
+  l121:
+  foo ();
+  l122:
+  foo ();
+  l123:
+  foo ();
+  l124:
+  foo ();
+  l125:
+  foo ();
+  l126:
+  foo ();
+  l127:
+  foo ();
+  l128:
+  foo ();
+  l129:;
+  return 42;
+}
diff --git a/gcc/testsuite/c-c++-common/asan/pr121389-4.c b/gcc/testsuite/c-c++-common/asan/pr121389-4.c
new file mode 100644
index 0000000..2f7b410
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/asan/pr121389-4.c
@@ -0,0 +1,6 @@
+// PR middle-end/121389
+// { dg-do compile { target musttail } }
+// { dg-options "-fsanitize=address -fdisable-tree-switchlower_O0" }
+// { dg-skip-if "" { *-*-* } { "*" } { "-O0" } }
+
+#include "pr121389-3.c"