From 3739bcc8c8e1c532223af7d8870be11fb5c7dac4 Mon Sep 17 00:00:00 2001
From: Matthew Malcomson <matthew.malcomson@arm.com>
Date: Fri, 15 Nov 2019 10:01:38 +0000
Subject: [mid-end][__RTL] Clean state despite invalid __RTL startwith passes

Hi there,

When compiling an __RTL function that has an invalid "startwith" pass we
currently don't run the dfinish cleanup pass. This means we ICE on the next
function.

This change ensures that all state is cleaned up for the next function
to run correctly.

As an example, before this change the following code would ICE when compiling
the function `foo2` because the "peephole2" pass is not run at optimisation
level -O0.

When compiled with
./aarch64-none-linux-gnu-gcc -O0 -S missed-pass-error.c -o test.s

```
int __RTL (startwith ("peephole2")) badfoo ()
{
(function "badfoo"
  (insn-chain
    (block 2
      (edge-from entry (flags "FALLTHRU"))
      (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
      (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
      (cinsn 10 (use (reg/i:SI x19)))
      (edge-to exit (flags "FALLTHRU"))
    ) ;; block 2
  ) ;; insn-chain
) ;; function "foo2"
}

int __RTL (startwith ("final")) foo2 ()
{
(function "foo2"
  (insn-chain
    (block 2
      (edge-from entry (flags "FALLTHRU"))
      (cnote 3 [bb 2] NOTE_INSN_BASIC_BLOCK)
      (cinsn 101 (set (reg:DI x19) (reg:DI x0)))
      (cinsn 10 (use (reg/i:SI x19)))
      (edge-to exit (flags "FALLTHRU"))
    ) ;; block 2
  ) ;; insn-chain
) ;; function "foo2"
}
```

Now it silently ignores the __RTL function and successfully compiles foo2.

regtest done on aarch64
regtest done on x86_64

OK for trunk?

gcc/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* passes.c (should_skip_pass_p): Always run "dfinish".

gcc/testsuite/ChangeLog:

2019-11-15  Matthew Malcomson  <matthew.malcomson@arm.com>

	* gcc.dg/rtl/aarch64/missed-pass-error.c: New test.

From-SVN: r278283
---
 gcc/passes.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'gcc/passes.c')

diff --git a/gcc/passes.c b/gcc/passes.c
index cfc0fef..b77356d 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -2375,7 +2375,8 @@ should_skip_pass_p (opt_pass *pass)
     return false;
 
   /* Don't skip df init; later RTL passes need it.  */
-  if (strstr (pass->name, "dfinit") != NULL)
+  if (strstr (pass->name, "dfinit") != NULL
+      || strstr (pass->name, "dfinish") != NULL)
     return false;
 
   if (!quiet_flag)
-- 
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