[Bug tree-optimization/104601] [11/12 Regression] Invalid branch elimination at -O2

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104601

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
But:
--- gcc/tree-ssa-sccvn.cc.jj    2022-02-11 00:19:22.432063254 +0100
+++ gcc/tree-ssa-sccvn.cc       2022-02-23 16:16:25.873557626 +0100
@@ -5218,7 +5218,11 @@ visit_reference_op_call (tree lhs, gcall

   if (vnresult)
     {
-      if (vnresult->result_vdef && vdef)
+      /* If stmt has non-SSA_NAME lhs, don't value number the vdef,
+        as the call still acts as a lhs store.  */
+      if (!lhs && vdef && gimple_call_lhs (stmt))
+       changed |= set_ssa_val_to (vdef, vdef);
+      else if (vnresult->result_vdef && vdef)
        changed |= set_ssa_val_to (vdef, vnresult->result_vdef);
       else if (vdef)
        /* If the call was discovered to be pure or const reflect
@@ -5248,7 +5252,10 @@ visit_reference_op_call (tree lhs, gcall
              if (TREE_CODE (fn) == ADDR_EXPR
                  && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
                  && (flags_from_decl_or_type (TREE_OPERAND (fn, 0))
-                     & (ECF_CONST | ECF_PURE)))
+                     & (ECF_CONST | ECF_PURE))
+                 /* If stmt has non-SSA_NAME lhs, don't value number the
+                    vdef, as the call still acts as a lhs store.  */
+                 && (lhs || gimple_call_lhs (stmt) == NULL_TREE))
                vdef_val = vuse_ssa_val (gimple_vuse (stmt));
            }
          changed |= set_ssa_val_to (vdef, vdef_val);
works for the testcase.