Correct a function pre/postcondition [PR102403].

[thirdparty/gcc.git] / gcc / function.c

diff --git a/gcc/function.c b/gcc/function.c
index 59fd72b0e820de69625fd493726bb9542ac100a0..af3d57b32a36785bd679ef6e35e57040c5f847ee 100644 (file)
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -1,5 +1,5 @@
 /* Expands front end tree to back end RTL for GCC.
-   Copyright (C) 1987-2020 Free Software Foundation, Inc.
+   Copyright (C) 1987-2021 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -82,6 +82,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimple.h"
 #include "options.h"
 #include "function-abi.h"
+#include "value-range.h"
+#include "gimple-range.h"
 
 /* So we can assign to cfun in this file.  */
 #undef cfun
@@ -1785,12 +1787,16 @@ instantiate_virtual_regs_in_insn (rtx_insn *insn)
        {
          error_for_asm (insn, "impossible constraint in %<asm%>");
          /* For asm goto, instead of fixing up all the edges
-            just clear the template and clear input operands
-            (asm goto doesn't have any output operands).  */
+            just clear the template and clear input and output operands
+            and strip away clobbers.  */
          if (JUMP_P (insn))
            {
              rtx asm_op = extract_asm_operands (PATTERN (insn));
+             PATTERN (insn) = asm_op;
+             PUT_MODE (asm_op, VOIDmode);
              ASM_OPERANDS_TEMPLATE (asm_op) = ggc_strdup ("");
+             ASM_OPERANDS_OUTPUT_CONSTRAINT (asm_op) = "";
+             ASM_OPERANDS_OUTPUT_IDX (asm_op) = 0;
              ASM_OPERANDS_INPUT_VEC (asm_op) = rtvec_alloc (0);
              ASM_OPERANDS_INPUT_CONSTRAINT_VEC (asm_op) = rtvec_alloc (0);
            }
@@ -2206,13 +2212,15 @@ use_register_for_decl (const_tree decl)
       /* Otherwise, if RESULT_DECL is DECL_BY_REFERENCE, it will take
         the function_result_decl's assignment.  Since it's a pointer,
         we can short-circuit a number of the tests below, and we must
-        duplicat e them because we don't have the
-        function_result_decl to test.  */
+        duplicate them because we don't have the function_result_decl
+        to test.  */
       if (!targetm.calls.allocate_stack_slots_for_args ())
        return true;
       /* We don't set DECL_IGNORED_P for the function_result_decl.  */
       if (optimize)
        return true;
+      if (cfun->tail_call_marked)
+       return true;
       /* We don't set DECL_REGISTER for the function_result_decl.  */
       return false;
     }
@@ -3028,7 +3036,15 @@ assign_parm_setup_block (struct assign_parm_data_all *all,
                  reg = gen_rtx_REG (word_mode, REGNO (entry_parm));
                  reg = convert_to_mode (mode, copy_to_reg (reg), 1);
                }
-             emit_move_insn (change_address (mem, mode, 0), reg);
+
+             /* We use adjust_address to get a new MEM with the mode
+                changed.  adjust_address is better than change_address
+                for this purpose because adjust_address does not lose
+                the MEM_EXPR associated with the MEM.
+
+                If the MEM_EXPR is lost, then optimizations like DSE
+                assume the MEM escapes and thus is not subject to DSE.  */
+             emit_move_insn (adjust_address (mem, mode, 0), reg);
            }
 
 #ifdef BLOCK_REG_PADDING
@@ -3819,9 +3835,16 @@ assign_parms (tree fndecl)
        {
          rtx real_decl_rtl;
 
-         real_decl_rtl = targetm.calls.function_value (TREE_TYPE (decl_result),
-                                                       fndecl, true);
-         REG_FUNCTION_VALUE_P (real_decl_rtl) = 1;
+         /* Unless the psABI says not to.  */
+         if (TYPE_EMPTY_P (TREE_TYPE (decl_result)))
+           real_decl_rtl = NULL_RTX;
+         else
+           {
+             real_decl_rtl
+               = targetm.calls.function_value (TREE_TYPE (decl_result),
+                                               fndecl, true);
+             REG_FUNCTION_VALUE_P (real_decl_rtl) = 1;
+           }
          /* The delay slot scheduler assumes that crtl->return_rtx
             holds the hard register containing the return value, not a
             temporary pseudo.  */
@@ -4850,6 +4873,8 @@ allocate_struct_function (tree fndecl, bool abstract_p)
      binding annotations among them.  */
   cfun->debug_nonbind_markers = lang_hooks.emits_begin_stmt
     && MAY_HAVE_DEBUG_MARKER_STMTS;
+
+  cfun->x_range_query = &global_ranges;
 }
 
 /* This is like allocate_struct_function, but pushes a new cfun for FNDECL
@@ -4924,6 +4949,9 @@ push_dummy_function (bool with_decl)
       fn_result_decl = build_decl (UNKNOWN_LOCATION, RESULT_DECL,
                                         NULL_TREE, void_type_node);
       DECL_RESULT (fn_decl) = fn_result_decl;
+      DECL_ARTIFICIAL (fn_decl) = 1;
+      tree fn_name = get_identifier (" ");
+      SET_DECL_ASSEMBLER_NAME (fn_decl, fn_name);
     }
   else
     fn_decl = NULL_TREE;
@@ -5397,9 +5425,11 @@ expand_function_end (void)
       tree decl_result = DECL_RESULT (current_function_decl);
       rtx decl_rtl = DECL_RTL (decl_result);
 
-      if (REG_P (decl_rtl)
-         ? REGNO (decl_rtl) >= FIRST_PSEUDO_REGISTER
-         : DECL_REGISTER (decl_result))
+      if ((REG_P (decl_rtl)
+          ? REGNO (decl_rtl) >= FIRST_PSEUDO_REGISTER
+          : DECL_REGISTER (decl_result))
+         /* Unless the psABI says not to.  */
+         && !TYPE_EMPTY_P (TREE_TYPE (decl_result)))
        {
          rtx real_decl_rtl = crtl->return_rtx;
          complex_mode cmode;