[UTC] Escape multiple {{ or }} in input for check lines. (#71790)

SCEV expressions may contain multiple {{ or }} in the debug output,
which needs escaping.

See
llvm/test/Analysis/LoopAccessAnalysis/loops-with-indirect-reads-and-writes.ll
for a test that needs escaping.

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/utils/UpdateTestChecks/common.py b/llvm/utils/UpdateTestChecks/common.py
index 74044f9..88b2ccc2 100644
--- a/llvm/utils/UpdateTestChecks/common.py
+++ b/llvm/utils/UpdateTestChecks/common.py
@@ -1171,6 +1171,9 @@ def generalize_check_lines_common(
         return match.group(1) + rv + match.group(match.lastindex)
 
     lines_with_def = []
+    multiple_braces_re = re.compile(r"({{+)|(}}+)")
+    def escape_braces(match_obj):
+        return '{{' + re.escape(match_obj.group(0)) + '}}'
 
     for i, line in enumerate(lines):
         if not is_asm and not is_analyze:
@@ -1200,6 +1203,10 @@ def generalize_check_lines_common(
                 (lines[i], changed) = nameless_value_regex.subn(
                     transform_line_vars, lines[i], count=1
                 )
+        if is_analyze:
+            # Escape multiple {{ or }} as {{}} denotes a FileCheck regex.
+            scrubbed_line = multiple_braces_re.sub(escape_braces, lines[i])
+            lines[i] = scrubbed_line
     return lines