[gcc r13-2811] testsuite: make check-functions-body dump expected and seen cases on failure.

[Tamar Christina <tnfchris@gcc.gnu.org>]

https://gcc.gnu.org/g:50324a0d39b9e9d47e8959d7f7f2460b16e8f2a2

commit r13-2811-g50324a0d39b9e9d47e8959d7f7f2460b16e8f2a2
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Fri Sep 23 10:56:30 2022 +0100

    testsuite: make check-functions-body dump expected and seen cases on failure.
    
    Often times when a check_function_body check fails it can be quite hard to
    figure out why as no additional information is provided.
    
    This changes it so that on failures it prints out the regex expression it's
    using and the text it's comparing against to the verbose log.
    
    This makes it much easier to figure out why a test has failed.
    
    gcc/testsuite/ChangeLog:
    
            * lib/scanasm.exp (check_function_body): Add debug output to verbose log
            on failure.

Diff:
---
 gcc/testsuite/lib/scanasm.exp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/lib/scanasm.exp b/gcc/testsuite/lib/scanasm.exp
index a80630bb2a8..7c9dcfc9b2e 100644
--- a/gcc/testsuite/lib/scanasm.exp
+++ b/gcc/testsuite/lib/scanasm.exp
@@ -803,7 +803,12 @@ proc check_function_body { functions name body_regexp } {
     if { ![info exists up_functions($name)] } {
 	return 0
     }
-    return [regexp "^$body_regexp\$" $up_functions($name)]
+    set fn_res [regexp "^$body_regexp\$" $up_functions($name)]
+    if { !$fn_res } {
+      verbose -log "body: $body_regexp"
+      verbose -log "against: $up_functions($name)"
+    }
+    return $fn_res
 }
 
 # Check the implementations of functions against expected output.  Used as: