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authorJeff Law <law@redhat.com>2019-04-03 10:03:37 -0600
committerJeff Law <law@gcc.gnu.org>2019-04-03 10:03:37 -0600
commit9427422ddacdf1c2914adfb6e8edca87f250fdfc (patch)
tree605d02db23777fe46d5df2e782b7896d79402aaf /gcc
parentc13e978820b82d7066ab29dc6b3c9a6d4848a91f (diff)
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re PR rtl-optimization/81025 (gcc ICE while building glibc for MIPS soft-float multi-lib variant)
PR rtl-optimization/81025 * reorg.c (skip_consecutive_labels): Do not skip past a BARRIER. From-SVN: r270129
Diffstat (limited to 'gcc')
-rw-r--r--gcc/ChangeLog5
-rw-r--r--gcc/reorg.c15
2 files changed, 19 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9149d9c..0d7c206 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2019-04-03 Jeff Law <law@redhat.com>
+
+ PR rtl-optimization/81025
+ * reorg.c (skip_consecutive_labels): Do not skip past a BARRIER.
+
2019-04-03 Richard Biener <rguenther@suse.de>
PR tree-optimization/84101
diff --git a/gcc/reorg.c b/gcc/reorg.c
index 84128a4..8134938 100644
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -137,7 +137,20 @@ skip_consecutive_labels (rtx label_or_return)
rtx_insn *label = as_a <rtx_insn *> (label_or_return);
- for (insn = label; insn != 0 && !INSN_P (insn); insn = NEXT_INSN (insn))
+ /* __builtin_unreachable can create a CODE_LABEL followed by a BARRIER.
+
+ Since reaching the CODE_LABEL is undefined behavior, we can return
+ any code label and we're OK at runtime.
+
+ However, if we return a CODE_LABEL which leads to a shrinked wrapped
+ epilogue, but the path does not have a prologue, then we will trip
+ a sanity check in the dwarf2 cfi code which wants to verify that
+ the CFIs are all the same on the traces leading to the epilogue.
+
+ So we explicitly disallow looking through BARRIERS here. */
+ for (insn = label;
+ insn != 0 && !INSN_P (insn) && !BARRIER_P (insn);
+ insn = NEXT_INSN (insn))
if (LABEL_P (insn))
label = insn;