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[COMMITTED] tree-optimization/103467 - Don't reuse reference after potential resize.

Message ID 8f4cea4d-9f7b-3ffd-e8da-f391af861f3a@redhat.com
State New
Headers show
Series [COMMITTED] tree-optimization/103467 - Don't reuse reference after potential resize. | expand

Commit Message

Andrew MacLeod Nov. 30, 2021, 1:06 a.m. UTC 
After making sure the vector is large enough, we use a reference to the 
object through the rest of the function.  One path however requests the 
def chain for a dependant ssa-name, and if that request caused a resize, 
then our reference is no longer valid. On this path, simply use the 
object directly.

Bootstrapped on x86_64-pc-linux-gnu with no regressions.  Pushed as obvious.

Andrew
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Patch

commit ab202b659dbdfd3a1f45ffe7a5052f35b5e8fa6d
Author: Andrew MacLeod <amacleod@redhat.com>
Date:   Mon Nov 29 19:53:50 2021 -0500

    Don't reuse reference after potential resize.
    
    When a new def chain is requested, any existing reference may no longer
    be valid, so just use the object directly.
    
            PR tree-optimization/103467
            * gimple-range-gori.cc (range_def_chain::register_dependency): Don't
            use an object reference after a potential resize.

diff --git a/gcc/gimple-range-gori.cc b/gcc/gimple-range-gori.cc
index 911d7ac4ec8..0dba34b58c5 100644
--- a/gcc/gimple-range-gori.cc
+++ b/gcc/gimple-range-gori.cc
@@ -278,11 +278,12 @@  range_def_chain::register_dependency (tree name, tree dep, basic_block bb)
     {
       // Get the def chain for the operand.
       b = get_def_chain (dep);
-      // If there was one, copy it into result.
+      // If there was one, copy it into result.  Access def_chain directly
+      // as the get_def_chain request above could reallocate the vector.
       if (b)
-	bitmap_ior_into (src.bm, b);
+	bitmap_ior_into (m_def_chain[v].bm, b);
       // And copy the import list.
-      set_import (src, NULL_TREE, get_imports (dep));
+      set_import (m_def_chain[v], NULL_TREE, get_imports (dep));
     }
   else
     // Originated outside the block, so it is an import.