[PATCH, i386]: Fix and improve a couple of builtin expansions

[Uros Bizjak]

Hello!

The missing return in _xgetbv is a bug and will be backported to
release branches.

2018-05-10  Uros Bizjak  <ubizjak@gmail.com>

    * config/i386/i386.c (ix86_expand_builtin) <case IX86_BUILTIN_RDPID>:
    Generate SImode target register for null target.
    <case IX86_BUILTIN_XGETBV>: Ditto.
    <case IX86_BUILTIN_XSETBV>: Optimize LSHIFTRT generation.
    * config/i386/xsaveintrin.h (_xgetbv): Add missing return.

testsuite/ChangeLog:

2018-05-10  Uros Bizjak  <ubizjak@gmail.com>

    * gcc.target/i386/xgetsetbv.c: Check also variable arguments.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Committed to mainline SVN.

Uros.
-------------- next part --------------
Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c	(revision 260116)
+++ config/i386/i386.c	(working copy)
@@ -37085,7 +37085,7 @@ ix86_expand_builtin (tree exp, rtx target, rtx sub
 
     case IX86_BUILTIN_RDPID:
 
-      op0 = gen_reg_rtx (TARGET_64BIT ? DImode : SImode);
+      op0 = gen_reg_rtx (word_mode);
 
       if (TARGET_64BIT)
 	{
@@ -37094,18 +37094,16 @@ ix86_expand_builtin (tree exp, rtx target, rtx sub
 	}
       else
 	insn = gen_rdpid (op0);
+
       emit_insn (insn);
 
-      if (target == 0)
-	{
-	  /* mode is VOIDmode if __builtin_rdpid has been called
-	     without lhs.  */
-	  if (mode == VOIDmode)
-	    return target;
-	  target = gen_reg_rtx (mode);
-	}
+      if (target == 0
+	  || !register_operand (target, SImode))
+	target = gen_reg_rtx (SImode);
+
       emit_move_insn (target, op0);
       return target;
+
     case IX86_BUILTIN_RDPMC:
     case IX86_BUILTIN_RDTSC:
     case IX86_BUILTIN_RDTSCP:
@@ -37164,14 +37162,9 @@ ix86_expand_builtin (tree exp, rtx target, rtx sub
 	  emit_move_insn (gen_rtx_MEM (SImode, op4), op2);
 	}
 
-      if (target == 0)
-	{
-	  /* mode is VOIDmode if __builtin_rd* has been called
-	     without lhs.  */
-	  if (mode == VOIDmode)
-	    return target;
-	  target = gen_reg_rtx (mode);
-	}
+      if (target == 0
+	  || !register_operand (target, DImode))
+        target = gen_reg_rtx (DImode);
 
       if (TARGET_64BIT)
 	{
@@ -37260,25 +37253,23 @@ ix86_expand_builtin (tree exp, rtx target, rtx sub
       if (!REG_P (op0))
 	op0 = copy_to_mode_reg (SImode, op0);
 
+      op1 = force_reg (DImode, op1);
+
       if (TARGET_64BIT)
 	{
 	  op2 = expand_simple_binop (DImode, LSHIFTRT, op1, GEN_INT (32),
 				     NULL, 1, OPTAB_DIRECT);
 
+	  icode = CODE_FOR_xsetbv_rex64;
+
 	  op2 = gen_lowpart (SImode, op2);
 	  op1 = gen_lowpart (SImode, op1);
-	  if (!REG_P (op1))
-	    op1 = copy_to_mode_reg (SImode, op1);
-	  if (!REG_P (op2))
-	    op2 = copy_to_mode_reg (SImode, op2);
-	  icode = CODE_FOR_xsetbv_rex64;
 	  pat = GEN_FCN (icode) (op0, op1, op2);
 	}
       else
 	{
-	  if (!REG_P (op1))
-	    op1 = copy_to_mode_reg (DImode, op1);
 	  icode = CODE_FOR_xsetbv;
+
 	  pat = GEN_FCN (icode) (op0, op1);
 	}
       if (pat)
Index: config/i386/xsaveintrin.h
===================================================================
--- config/i386/xsaveintrin.h	(revision 260116)
+++ config/i386/xsaveintrin.h	(working copy)
@@ -59,7 +59,7 @@ extern __inline long long
 __attribute__((__gnu_inline__, __always_inline__, __artificial__))
 _xgetbv (unsigned int __A)
 {
-  __builtin_ia32_xgetbv (__A);
+  return __builtin_ia32_xgetbv (__A);
 }
 
 #ifdef __x86_64__
Index: testsuite/gcc.target/i386/xgetsetbv.c
===================================================================
--- testsuite/gcc.target/i386/xgetsetbv.c	(revision 260116)
+++ testsuite/gcc.target/i386/xgetsetbv.c	(working copy)
@@ -1,13 +1,27 @@
 /* { dg-do compile } */
 /* { dg-options "-O2 -mxsave" } */
-/* { dg-final { scan-assembler "xgetbv" } } */
-/* { dg-final { scan-assembler "xsetbv" } } */
+/* { dg-final { scan-assembler-times "xgetbv" 3 } } */
+/* { dg-final { scan-assembler-times "xsetbv" 3 } } */
 
 #include <x86intrin.h>
 
-unsigned int
-xgetsetbv (void)
+unsigned long long
+foo (unsigned x, unsigned y)
 {
+ _xsetbv (x, y);
+  return _xgetbv (x);
+}
+
+unsigned long long
+bar (unsigned x, unsigned long long y)
+{
+ _xsetbv (x, y);
+  return _xgetbv (x);
+}
+
+unsigned long long
+baz (void)
+{
  _xsetbv (0, 0);
   return _xgetbv (0);
 }