Re: [PATCH v3] tests/qht-bench: Fix Clang 'implicit-int-float-conversion' warning

[Emilio G. Cota]

On Mon, May 04, 2020 at 16:43:52 +0200, Philippe Mathieu-Daudé wrote:
> When building with Clang 10 on Fedora 32, we get:
> 
>   tests/qht-bench.c:287:29: error: implicit conversion from 'unsigned long' 
> to 'double' changes value from 18446744073709551615 to 18446744073709551616 
> [-Werror,-Wimplicit-int-float-conversion]
(snip)
> @@ -284,7 +285,7 @@ static void do_threshold(double rate, uint64_t *threshold)
>  if (rate == 1.0) {
>  *threshold = UINT64_MAX;
>  } else {
> -*threshold = rate * UINT64_MAX;
> +*threshold = rate * nextafter(0x1p64, 0.0);

Reviewed-by: Emilio G. Cota 

Please consider mentioning 25f74087c69 in the commit log -- it clearly
describes the problem.

Thanks,

Emilio

Re: [PATCH v3] tests/qht-bench: Fix Clang 'implicit-int-float-conversion' warning

[no-reply]

Patchew URL: https://patchew.org/QEMU/20200504144352.23021-1-phi...@redhat.com/



Hi,

This series failed the docker-mingw@fedora build test. Please find the testing 
commands and
their output below. If you have Docker installed, you can probably reproduce it
locally.

=== TEST SCRIPT BEGIN ===
#! /bin/bash
export ARCH=x86_64
make docker-image-fedora V=1 NETWORK=1
time make docker-test-mingw@fedora J=14 NETWORK=1
=== TEST SCRIPT END ===




The full log is available at
http://patchew.org/logs/20200504144352.23021-1-phi...@redhat.com/testing.docker-mingw@fedora/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-de...@redhat.com

[PATCH v3] tests/qht-bench: Fix Clang 'implicit-int-float-conversion' warning

[Philippe Mathieu-Daudé]

When building with Clang 10 on Fedora 32, we get:

  tests/qht-bench.c:287:29: error: implicit conversion from 'unsigned long' to 
'double' changes value from 18446744073709551615 to 18446744073709551616 
[-Werror,-Wimplicit-int-float-conversion]
  *threshold = rate * UINT64_MAX;
~ ^~
  /usr/include/stdint.h:130:23: note: expanded from macro 'UINT64_MAX'
  # define UINT64_MAX (__UINT64_C(18446744073709551615))
   ^~~~
  /usr/include/stdint.h:107:25: note: expanded from macro '__UINT64_C'
  #  define __UINT64_C(c) c ## UL
  ^~~
  :14:1: note: expanded from here
  18446744073709551615UL
  ^~

Fix by using nextafter() from :

  double nextafter( double from, double to );

  Returns the next representable value of 'from'
  in the direction of 'to'.

Signed-off-by: Philippe Mathieu-Daudé 
---
Supersedes: <20200504144125.22435-1-phi...@redhat.com>

Since v2: corrected patch subject
Since v1: nextafterf() -> nextafter()

Cc: Emilio G. Cota 
Cc: Alex Bennée 
Cc: Richard Henderson 
Cc: Alexander Bulekov 
---
 tests/qht-bench.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/qht-bench.c b/tests/qht-bench.c
index e3b512f26f..54ce1e8188 100644
--- a/tests/qht-bench.c
+++ b/tests/qht-bench.c
@@ -10,6 +10,7 @@
 #include "qemu/qht.h"
 #include "qemu/rcu.h"
 #include "qemu/xxhash.h"
+#include 
 
 struct thread_stats {
 size_t rd;
@@ -284,7 +285,7 @@ static void do_threshold(double rate, uint64_t *threshold)
 if (rate == 1.0) {
 *threshold = UINT64_MAX;
 } else {
-*threshold = rate * UINT64_MAX;
+*threshold = rate * nextafter(0x1p64, 0.0);
 }
 }
 
-- 
2.21.3