re PR rtl-optimization/87817 (gcc.target/i386/bmi2-bzhi-2.c execution test)

	PR rtl-optimization/87817
	* config/i386/i386.c (ix86_fold_builtin): For _bzhi_u{32,64} if
	last argument has low 8 bits clear, fold to 0.

	* gcc.target/i386/bmi2-bzhi-3.c (main): Add a couple of new tests.

From-SVN: r266140

gcc/ChangeLog

+2018-11-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/87817
+	* config/i386/i386.c (ix86_fold_builtin): For _bzhi_u{32,64} if
+	last argument has low 8 bits clear, fold to 0.
+
 2018-11-14  Iain Sandoe  <iain@sandoe.co.uk>
 
 	* tree-vect-data-refs.c (vect_can_force_dr_alignment_p): Cast

gcc/config/i386/i386.c

@@ -32671,6 +32671,8 @@ ix86_fold_builtin (tree fndecl, int n_args,
 	      unsigned int idx = tree_to_uhwi (args[1]) & 0xff;
 	      if (idx >= TYPE_PRECISION (TREE_TYPE (args[0])))
 		return args[0];
+	      if (idx == 0)
+		return build_int_cst (TREE_TYPE (TREE_TYPE (fndecl)), 0);
 	      if (!tree_fits_uhwi_p (args[0]))
 		break;
 	      unsigned HOST_WIDE_INT res = tree_to_uhwi (args[0]);

gcc/testsuite/ChangeLog

+2018-11-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/87817
+	* gcc.target/i386/bmi2-bzhi-3.c (main): Add a couple of new tests.
+
 2018-11-14  Wilco Dijkstra  <wdijkstr@arm.com>  
 
 	* gcc.target/aarch64/pr62178.c: Relax scan-assembler checks.

gcc/testsuite/gcc.target/i386/bmi2-bzhi-3.c

@@ -58,7 +58,11 @@ main ()
     link_error ();
   if (_bzhi_u32 (c, 32) != c
       || _bzhi_u32 (c, 64) != c
-      || _bzhi_u32 (c, 255) != c)
+      || _bzhi_u32 (c, 255) != c
+      || _bzhi_u32 (c, 544) != c
+      || _bzhi_u32 (c, 0) != 0
+      || _bzhi_u32 (c, 256) != 0
+      || _bzhi_u32 (c, 1024) != 0)
     link_error ();
 #ifdef __x86_64__
   if (f21 () != 0 || f22 (-1ULL) != 0
@@ -70,7 +74,11 @@ main ()
       || f33 () != -1ULL || f34 (-1ULL) != -1ULL)
     link_error ();
   if (_bzhi_u64 (d, 64) != d
-      || _bzhi_u64 (d, 255) != d)
+      || _bzhi_u64 (d, 255) != d
+      || _bzhi_u64 (d, 576) != d
+      || _bzhi_u64 (d, 0) != 0
+      || _bzhi_u64 (d, 256) != 0
+      || _bzhi_u64 (d, 512) != 0)
     link_error ();
 #endif
   return 0;