i386: Fix ICE caused by ix86_emit_i387_log1p [PR105214]

The following testcase ICEs, because ix86_emit_i387_log1p attempts to
emit something like
  if (cond)
    some_code1;
  else
    some_code2;
and emits a conditional jump using emit_jump_insn (standard way in
the file) and an unconditional jump using emit_jump.
The problem with that is that if there is pending stack adjustment,
it isn't emitted before the conditional jump, but is before the
unconditional jump and therefore stack is adjusted only conditionally
(at the end of some_code1 above), which makes dwarf2 pass unhappy about it
but is a serious wrong-code even if it doesn't ICE.

This can be fixed either by emitting pending stack adjust before the
conditional jump as the following patch does, or by not using
  emit_jump (label2);
and instead hand inlining what that function does except for the
pending stack adjustment, like:
  emit_jump_insn (targetm.gen_jump (label2));
  emit_barrier ();
In that case there will be no stack adjustment in the sequence and
it will be done later on somewhere else.

2022-04-12  Jakub Jelinek  <jakub@redhat.com>

	PR target/105214
	* config/i386/i386-expand.cc (ix86_emit_i387_log1p): Call
	do_pending_stack_adjust.

	* gcc.dg/asan/pr105214.c: New test.

diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 794315e..f6f2c1e 100644 (file)
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -17291,6 +17291,11 @@ void ix86_emit_i387_log1p (rtx op0, rtx op1)
   rtx cst, cstln2, cst1;
   rtx_insn *insn;
 
+  /* The emit_jump call emits pending stack adjust, make sure it is emitted
+     before the conditional jump, otherwise the stack adjustment will be
+     only conditional.  */
+  do_pending_stack_adjust ();
+
   cst = const_double_from_real_value
     (REAL_VALUE_ATOF ("0.29289321881345247561810596348408353", XFmode), XFmode);
   cstln2 = force_reg (XFmode, standard_80387_constant_rtx (4)); /* fldln2 */

diff --git a/gcc/testsuite/gcc.dg/asan/pr105214.c b/gcc/testsuite/gcc.dg/asan/pr105214.c
new file mode 100644 (file)
index 0000000..a755336
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr105214.c
@@ -0,0 +1,16 @@
+/* PR target/105214 */
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "*" } { "-O2" } } */
+/* { dg-options "-Ofast -fnon-call-exceptions -fexceptions -fstack-check=generic -fsanitize=address -fno-finite-math-only -fsignaling-nans -fno-associative-math" } */
+
+float f;
+void bar (int *);
+
+void
+foo (void)
+{
+  int a[1600], b[1];
+  f += __builtin_log1pf (f);
+  bar (a);
+  bar (b);
+}