This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

regcprop.c bug fix

So while tracking down a hairy address reload for an output reload bug, copyprop_hardreg_forward_1 was faulting because it was trying to extract move patterns that didn't work out, and when it came back to the code, it then tries to access recog_data, but the problem is, the exploration of other instructions to see if they match, overwrites that data, and there is nothing that restores the data to a point in which the code below this point expects.  It uses recog_data.operand[i], where i is limited by n_ops, but that value corresponded to the old data in recog_data.  The recog and extract_insn in insn_invalid_p called from verify_changes called from apply_change_group called from validate_change wipes the `old' recog_data with new data.  This data, for example, might only have 2 operands, with an invalid value for the third operand.  The old n_ops, might well be 3 from the original data.  Accessing that data can cause a crash.

So, I don't know if people want to data regenerated, or it they want to cache the data, or if they want to save and restore it underneath a called api...


Index: regcprop.c
--- regcprop.c	(revision 1831)
+++ regcprop.c	(working copy)
@@ -866,6 +866,10 @@ copyprop_hardreg_forward_1 (basic_block
+      extract_insn (insn);
+      if (! constrain_operands (1))
+	fatal_insn_not_found (insn);
+      preprocess_constraints ();
       any_replacements = false;

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]