[PATCH 01/14] testsuite: Add clz_ifn and ctz_ifn effective targets

[ktkachov]

From: Kyrylo Tkachov <ktkac...@nvidia.com>

A GIMPLE FE test with a .CLZ or .CTZ call needs the clz or ctz
instruction pattern for the mode of the call, because the expansion of
these internal functions has no fallback.  The clz and ctz effective
targets only check that __builtin_clz and __builtin_ctz do not become
library calls.  They are also true when the expander makes the count
from other patterns, for example ctz on s390 before z17.

Add clz_ifn and ctz_ifn.  They check that niter analysis turns a
counting loop on unsigned int into a .CLZ or .CTZ call, which it does
only if the target has the instruction pattern.

Bootstrapped and tested on aarch64-none-linux-gnu and x86_64-linux.

gcc/ChangeLog:

        * doc/sourcebuild.texi (clz_ifn, ctz_ifn): Document.

gcc/testsuite/ChangeLog:

        * lib/target-supports.exp (check_effective_target_clz_ifn)
        (check_effective_target_ctz_ifn): New procedures.

Signed-off-by: Kyrylo Tkachov <ktkac...@nvidia.com>
---
 gcc/doc/sourcebuild.texi              |  8 ++++++
 gcc/testsuite/lib/target-supports.exp | 38 +++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index 3aa9fcbb577..822e4df53a4 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -2774,6 +2774,10 @@ Target supports a clz optab on long.
 @item clzll
 Target supports a clz optab on long long.
 
+@item clz_ifn
+Target expands a @code{.CLZ} internal function call on @code{unsigned int}
+with an instruction pattern.
+
 @item ctz
 Target supports a ctz optab on int.
 
@@ -2783,6 +2787,10 @@ Target supports a ctz optab on long.
 @item ctzll
 Target supports a ctz optab on long long.
 
+@item ctz_ifn
+Target expands a @code{.CTZ} internal function call on @code{unsigned int}
+with an instruction pattern.
+
 @item cmpccxadd
 Target supports the execution of @code{cmpccxadd} instructions.
 
diff --git a/gcc/testsuite/lib/target-supports.exp 
b/gcc/testsuite/lib/target-supports.exp
index ae04b6a8daa..ad27992c6db 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -10726,6 +10726,44 @@ proc check_effective_target_ctzll { } {
     } "" ]
 }
 
+# Return 1 if the target expands a .CLZ call on unsigned int with an
+# instruction pattern.  Niter analysis turns the loop into such a call
+# only in that case.
+
+proc check_effective_target_clz_ifn { } {
+    return [check_no_messages_and_pattern clz_ifn "\\.CLZ \\(" tree-optimized {
+       int foo (unsigned int b)
+         {
+           int c = 0;
+           while (b)
+             {
+               b >>= 1;
+               c++;
+             }
+           return c;
+         }
+    } "-O2" ]
+}
+
+# Return 1 if the target expands a .CTZ call on unsigned int with an
+# instruction pattern.  Niter analysis turns the loop into such a call
+# only in that case.
+
+proc check_effective_target_ctz_ifn { } {
+    return [check_no_messages_and_pattern ctz_ifn "\\.CTZ \\(" tree-optimized {
+       int foo (unsigned int b)
+         {
+           int c = 0;
+           while (b)
+             {
+               b <<= 1;
+               c++;
+             }
+           return c;
+         }
+    } "-O2" ]
+}
+
 # Return 1 if the target supports atomic operations on "long long"
 # and can execute them.
 #
-- 
2.54.0 (Apple Git-157)