tree-optimization/98786 - fix issue with phiopt and abnormals

This fixes factor_out_conditional_conversion to avoid creating overlapping
lifetimes for abnormals.  It also makes sure we do deal with a conditional
conversion (at least for one PHI arg def) - for the testcase that wasn't the case.

2021-01-22  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/98786
	* tree-ssa-phiopt.c (factor_out_conditional_conversion): Avoid
	adding new uses of abnormals.  Verify we deal with a conditional
	conversion.

	* gcc.dg/torture/pr98786.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/torture/pr98786.c b/gcc/testsuite/gcc.dg/torture/pr98786.c
new file mode 100644 (file)
index 0000000..ea36471
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr98786.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-fno-tree-dce" } */
+
+void
+func_30 (void);
+
+int __attribute__ ((pure, returns_twice))
+func_38 (int g_15, int p_39)
+{
+  return !!g_15 ? p_39 : 0;
+}
+
+void
+func_26 (int func_26___trans_tmp_1)
+{
+  long int l_37 = 0;
+  int __trans_tmp_1;
+
+  func_26___trans_tmp_1 = func_38 (func_26___trans_tmp_1, 1);
+  __trans_tmp_1 = func_38 (func_26___trans_tmp_1, l_37);
+  l_37 = 1;
+  func_30 ();
+}

diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index bbc78af..ddd9d53 100644 (file)
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -474,6 +474,9 @@ factor_out_conditional_conversion (edge e0, edge e1, gphi *phi,
       if (!is_gimple_reg_type (TREE_TYPE (new_arg0)))
        return NULL;
     }
+  if (TREE_CODE (new_arg0) == SSA_NAME
+      && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_arg0))
+    return NULL;
 
   if (TREE_CODE (arg1) == SSA_NAME)
     {
@@ -484,13 +487,25 @@ factor_out_conditional_conversion (edge e0, edge e1, gphi *phi,
          || gimple_assign_rhs_code (arg1_def_stmt) != convert_code)
        return NULL;
 
+      /* Either arg1_def_stmt or arg0_def_stmt should be conditional.  */
+      if (dominated_by_p (CDI_DOMINATORS, gimple_bb (phi), gimple_bb (arg0_def_stmt))
+         && dominated_by_p (CDI_DOMINATORS,
+                            gimple_bb (phi), gimple_bb (arg1_def_stmt)))
+       return NULL;
+
       /* Use the RHS as new_arg1.  */
       new_arg1 = gimple_assign_rhs1 (arg1_def_stmt);
       if (convert_code == VIEW_CONVERT_EXPR)
        new_arg1 = TREE_OPERAND (new_arg1, 0);
+      if (TREE_CODE (new_arg1) == SSA_NAME
+         && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_arg1))
+       return NULL;
     }
   else
     {
+      /* arg0_def_stmt should be conditional.  */
+      if (dominated_by_p (CDI_DOMINATORS, gimple_bb (phi), gimple_bb (arg0_def_stmt)))
+       return NULL;
       /* If arg1 is an INTEGER_CST, fold it to new type.  */
       if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0))
          && int_fits_type_p (arg1, TREE_TYPE (new_arg0)))