[3/10] Add available_vector_sizes to target-supports.exp

[Richard Sandiford]

This patch adds a routine that lists the available vector sizes
for a target and uses it for some existing target conditions.
Later patches add more uses.

The cases are taken from multiple_sizes.


2017-11-03  Richard Sandiford  <richard.sandif...@linaro.org>
            Alan Hayward  <alan.hayw...@arm.com>
            David Sherwood  <david.sherw...@arm.com>

gcc/testsuite/
        * lib/target-supports.exp (available_vector_sizes): New proc.
        (check_effective_target_vect_multiple_sizes): Use it.
        (check_effective_target_vect64): Likewise.
        (check_effective_target_vect_sizes_32B_16B): Likewise.

Index: gcc/testsuite/lib/target-supports.exp
===================================================================
--- gcc/testsuite/lib/target-supports.exp       2017-11-03 12:16:58.605777011 
+0000
+++ gcc/testsuite/lib/target-supports.exp       2017-11-03 16:06:12.625838683 
+0000
@@ -6581,46 +6581,38 @@ foreach N {2 3 4 8} {
     }]
 }
 
-# Return 1 if the target supports multiple vector sizes
+# Return the list of vector sizes (in bits) that each target supports.
+# A vector length of "0" indicates variable-length vectors.
 
-proc check_effective_target_vect_multiple_sizes { } {
-    global et_vect_multiple_sizes_saved
-    global et_index
-
-    set et_vect_multiple_sizes_saved($et_index) 0
-    if { [istarget aarch64*-*-*]
-        || [is-effective-target arm_neon]
-        || (([istarget i?86-*-*] || [istarget x86_64-*-*])
-            && ([check_avx_available] && ![check_prefer_avx128])) } {
-       set et_vect_multiple_sizes_saved($et_index) 1
+proc available_vector_sizes { } {
+    set result {}
+    if { [istarget aarch64*-*-*] } {
+       lappend result 128 64
+    } elseif { [istarget arm*-*-*]
+               && [check_effective_target_arm_neon_ok] } {
+       lappend result 128 64
+    } elseif { (([istarget i?86-*-*] || [istarget x86_64-*-*])
+                && ([check_avx_available] && ![check_prefer_avx128])) } {
+       lappend result 256 128
+    } elseif { [istarget sparc*-*-*] } {
+       lappend result 64
+    } else {
+       # The traditional default asumption.
+       lappend result 128
     }
+    return $result
+}
+
+# Return 1 if the target supports multiple vector sizes
 
-    verbose "check_effective_target_vect_multiple_sizes:\
-            returning $et_vect_multiple_sizes_saved($et_index)" 2
-    return $et_vect_multiple_sizes_saved($et_index)
+proc check_effective_target_vect_multiple_sizes { } {
+    return [expr { [llength [available_vector_sizes]] > 1 }]
 }
 
 # Return 1 if the target supports vectors of 64 bits.
 
 proc check_effective_target_vect64 { } {
-    global et_vect64_saved
-    global et_index
-
-    if [info exists et_vect64_saved($et_index)] {
-        verbose "check_effective_target_vect64: using cached result" 2
-    } else {
-       set et_vect64_saved($et_index) 0
-        if { ([is-effective-target arm_neon]
-             && [check_effective_target_arm_little_endian])
-            || [istarget aarch64*-*-*]
-             || [istarget sparc*-*-*] } {
-          set et_vect64_saved($et_index) 1
-        }
-    }
-
-    verbose "check_effective_target_vect64:\
-            returning $et_vect64_saved($et_index)" 2
-    return $et_vect64_saved($et_index)
+    return [expr { [lsearch -exact [available_vector_sizes] 64] >= 0 }]
 }
 
 # Return 1 if the target supports vector copysignf calls.
@@ -7747,11 +7739,7 @@ proc check_avx_available { } {
 # Return true if 32- and 16-bytes vectors are available.
 
 proc check_effective_target_vect_sizes_32B_16B { } {
-  if { [check_avx_available] && ![check_prefer_avx128] } {
-     return 1;
-  } else {
-    return 0;
-  }
+    return [expr { [available_vector_sizes] == [list 256 128] }]
 }
 
 # Return true if 16- and 8-bytes vectors are available.