[gcc(refs/users/aoliva/heads/testme)] make sincos take type from intrinsic formal, not from result assignment

[Alexandre Oliva <aoliva@gcc.gnu.org>]

https://gcc.gnu.org/g:60f4c1120c99d16e3a80b6ee892c862be0513220

commit 60f4c1120c99d16e3a80b6ee892c862be0513220
Author: Alexandre Oliva <oliva@adacore.com>
Date:   Tue Sep 29 09:50:05 2020 -0300

    make sincos take type from intrinsic formal, not from result assignment
    
    This is a first step towards enabling the sincos optimization in Ada.
    
    The issue this patch solves is that sincos takes the type to be looked
    up with mathfn_built_in from variables or temporaries passed to sin
    and cos as arguments.  In Ada, sin and cos are declared in an internal
    aux package, with uses thereof in a standard generic package, which
    ensures that the types are not what mathfn_built_in expects.
    
    Taking the type from the intrinsic's formal parameter, as in the
    patch, ensures we get the type associated with the intrinsics,
    regardless of the types used to declare and import them, so the lookup
    of the CEXPI intrinsic for the same type finds it.
    
    
    for  gcc/ChangeLog
    
            * tree-ssa-math-opts.c (execute_cse_sincos_1): Take the type
            for the cexpi/sincos intrinsic interface from formals of other
            intrinsics.

Diff:
---
 gcc/tree-ssa-math-opts.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
index 8423caa3ee3..31fd241e69a 100644
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -1139,7 +1139,7 @@ execute_cse_sincos_1 (tree name)
 {
   gimple_stmt_iterator gsi;
   imm_use_iterator use_iter;
-  tree fndecl, res, type;
+  tree fndecl = NULL_TREE, res, type = NULL_TREE;
   gimple *def_stmt, *use_stmt, *stmt;
   int seen_cos = 0, seen_sin = 0, seen_cexpi = 0;
   auto_vec<gimple *> stmts;
@@ -1147,7 +1147,6 @@ execute_cse_sincos_1 (tree name)
   int i;
   bool cfg_changed = false;
 
-  type = TREE_TYPE (name);
   FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, name)
     {
       if (gimple_code (use_stmt) != GIMPLE_CALL
@@ -1169,15 +1168,34 @@ execute_cse_sincos_1 (tree name)
 	  break;
 
 	default:;
+	  continue;
 	}
-    }
 
+      tree t = TREE_VALUE (TYPE_ARG_TYPES (gimple_call_fntype (use_stmt)));
+      if (!type)
+	type = t;
+      else if (t != type)
+	{
+	  if (!tree_nop_conversion_p (type, t))
+	    return false;
+	  /* If there is more than one type to choose from, prefer one
+	     that has a CEXPI builtin.  */
+	  else if (!fndecl
+		   && (fndecl = mathfn_built_in (t, BUILT_IN_CEXPI)))
+	    type = t;
+	}
+    }
   if (seen_cos + seen_sin + seen_cexpi <= 1)
     return false;
 
+  if (type != TREE_TYPE (name)
+      && !tree_nop_conversion_p (type, TREE_TYPE (name)))
+    return false;
+
   /* Simply insert cexpi at the beginning of top_bb but not earlier than
      the name def statement.  */
-  fndecl = mathfn_built_in (type, BUILT_IN_CEXPI);
+  if (!fndecl)
+    fndecl = mathfn_built_in (type, BUILT_IN_CEXPI);
   if (!fndecl)
     return false;
   stmt = gimple_build_call (fndecl, 1, name);