Improve bgemm and sbgemm testing

- Fixes wrong return type for `is_close`
- Adds stricter compiler flags for test files so we don't see the above
issue again
- Re-uses test helper functions between compare_sgemm_sbgemm/bgemm.c

test/Makefile

@@ -13,7 +13,7 @@
 # 3. Neither the name of the OpenBLAS project nor the names of
 #    its contributors may be used to endorse or promote products
 #    derived from this software without specific prior written permission.
-# 
+#
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
@@ -34,6 +34,7 @@ ifneq (, $(filter $(CORE),LOONGSON3R3 LOONGSON3R4))
 endif
         override FFLAGS += -fno-tree-vectorize
 endif
+override CFLAGS += -std=c11 -Wall -Werror
 
 SUPPORT_GEMM3M = 0
 
@@ -402,10 +403,10 @@ zblat3 : zblat3.$(SUFFIX) ../$(LIBNAME)
 endif
 
 ifeq ($(BUILD_BFLOAT16),1)
-test_bgemm : compare_sgemm_bgemm.c ../$(LIBNAME)
+test_bgemm : compare_sgemm_bgemm.c test_helpers.h ../$(LIBNAME)
 	$(CC) $(CLDFLAGS) -o test_bgemm compare_sgemm_bgemm.c ../$(LIBNAME) $(EXTRALIB) $(CEXTRALIB)
 
-test_sbgemm : compare_sgemm_sbgemm.c ../$(LIBNAME)
+test_sbgemm : compare_sgemm_sbgemm.c test_helpers.h ../$(LIBNAME)
 	$(CC) $(CLDFLAGS) -o test_sbgemm compare_sgemm_sbgemm.c ../$(LIBNAME) $(EXTRALIB) $(CEXTRALIB)
 endif
 

test/compare_sgemm_bgemm.c

@@ -28,20 +28,13 @@ THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <stdint.h>
 #include <stdio.h>
 
+#include "test_helpers.h"
 
 #define SGEMM BLASFUNC(sgemm)
 #define BGEMM BLASFUNC(bgemm)
 #define BGEMM_LARGEST 256
 
-static float float16to32(bfloat16 value)
-{
-  blasint one = 1;
-  float result;
-  sbf16tos_(&one, &value, &one, &result, &one);
-  return result;
-}
-
-static float truncate_float(float value) {
+static float truncate_float32_to_bfloat16(float value) {
   blasint one = 1;
   bfloat16 tmp;
   float result;
@@ -50,17 +43,6 @@ static float truncate_float(float value) {
   return result;
 }
 
-static void *malloc_safe(size_t size) {
-  if (size == 0)
-    return malloc(1);
-  else
-    return malloc(size);
-}
-
-static float is_close(float a, float b, float rtol, float atol) {
-  return fabs(a - b) <= (atol + rtol*fabs(b));
-}
-
 int
 main (int argc, char *argv[])
 {
@@ -151,15 +133,15 @@ main (int argc, char *argv[])
               DD[i * m + j] +=
                 float16to32 (AA[k * j + l]) * float16to32 (BB[i + l * n]);
             }
-          if (!is_close(float16to32(CC[i * m + j]), truncate_float(C[i * m + j]), 0.01, 0.001)) {
+          if (!is_close(float16to32(CC[i * m + j]), truncate_float32_to_bfloat16(C[i * m + j]), 0.01, 0.001)) {
             printf("Mismatch at i=%d, j=%d, k=%d: CC=%.6f, C=%.6f\n",
-                    i, j, k, float16to32(CC[i * m + j]), truncate_float(C[i * m + j]));
+                    i, j, k, float16to32(CC[i * m + j]), truncate_float32_to_bfloat16(C[i * m + j]));
             ret++;
           }
 
-          if (!is_close(float16to32(CC[i * m + j]), truncate_float(DD[i * m + j]), 0.0001, 0.00001)) {
+          if (!is_close(float16to32(CC[i * m + j]), truncate_float32_to_bfloat16(DD[i * m + j]), 0.0001, 0.00001)) {
             printf("Mismatch at i=%d, j=%d, k=%d: CC=%.6f, DD=%.6f\n",
-                    i, j, k, float16to32(CC[i * m + j]), truncate_float(DD[i * m + j]));
+                    i, j, k, float16to32(CC[i * m + j]), truncate_float32_to_bfloat16(DD[i * m + j]));
             ret++;
           }
             

test/compare_sgemm_sbgemm.c

@@ -27,72 +27,15 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <stdio.h>
 #include <stdint.h>
 #include "../common.h"
+
+#include "test_helpers.h"
+
 #define SGEMM   BLASFUNC(sgemm)
 #define SBGEMM   BLASFUNC(sbgemm)
 #define SGEMV   BLASFUNC(sgemv)
 #define SBGEMV   BLASFUNC(sbgemv)
-typedef union
-{
-  unsigned short v;
-#if defined(_AIX)
-  struct __attribute__((packed))
-#else
-  struct
-#endif
-  {
-#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-    unsigned short s:1;
-    unsigned short e:8;
-    unsigned short m:7;
-#else
-    unsigned short m:7;
-    unsigned short e:8;
-    unsigned short s:1;
-#endif
-  } bits;
-} bfloat16_bits;
-
-typedef union
-{
-  float v;
-#if defined(_AIX)
-  struct __attribute__((packed))
-#else
-  struct
-#endif
-  {
-#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-    uint32_t s:1;
-    uint32_t e:8;
-    uint32_t m:23;
-#else
-    uint32_t m:23;
-    uint32_t e:8;
-    uint32_t s:1;
-#endif
-  } bits;
-} float32_bits;
-
-float
-float16to32 (bfloat16_bits f16)
-{
-  float32_bits f32;
-  f32.bits.s = f16.bits.s;
-  f32.bits.e = f16.bits.e;
-  f32.bits.m = (uint32_t) f16.bits.m << 16;
-  return f32.v;
-}
-
 #define SBGEMM_LARGEST  256
 
-void *malloc_safe(size_t size)
-{
-  if (size == 0)
-    return malloc(1);
-  else
-    return malloc(size);
-}
-
 int
 main (int argc, char *argv[])
 {
@@ -111,14 +54,13 @@ main (int argc, char *argv[])
     float *A = (float *)malloc_safe(m * k * sizeof(FLOAT));
     float *B = (float *)malloc_safe(k * n * sizeof(FLOAT));
     float *C = (float *)malloc_safe(m * n * sizeof(FLOAT));
-    bfloat16_bits *AA = (bfloat16_bits *)malloc_safe(m * k * sizeof(bfloat16_bits));
-    bfloat16_bits *BB = (bfloat16_bits *)malloc_safe(k * n * sizeof(bfloat16_bits));
+    bfloat16 *AA = (bfloat16 *)malloc_safe(m * k * sizeof(bfloat16));
+    bfloat16 *BB = (bfloat16 *)malloc_safe(k * n * sizeof(bfloat16));
     float *DD = (float *)malloc_safe(m * n * sizeof(FLOAT));
     float *CC = (float *)malloc_safe(m * n * sizeof(FLOAT));
     if ((A == NULL) || (B == NULL) || (C == NULL) || (AA == NULL) || (BB == NULL) ||
         (DD == NULL) || (CC == NULL))
       return 1;
-    bfloat16 atmp,btmp;
     blasint one=1;
 
     for (j = 0; j < m; j++)
@@ -126,8 +68,7 @@ main (int argc, char *argv[])
       for (i = 0; i < k; i++)
       {
         A[j * k + i] = ((FLOAT) rand () / (FLOAT) RAND_MAX) + 0.5;
-        sbstobf16_(&one, &A[j*k+i], &one, &atmp, &one);
-        AA[j * k + i].v = atmp;
+        sbstobf16_(&one, &A[j*k+i], &one, &AA[j * k + i], &one);
       }
     }
     for (j = 0; j < n; j++)
@@ -135,8 +76,7 @@ main (int argc, char *argv[])
       for (i = 0; i < k; i++)
       {
         B[j * k + i] = ((FLOAT) rand () / (FLOAT) RAND_MAX) + 0.5;
-        sbstobf16_(&one, &B[j*k+i], &one, &btmp, &one);
-        BB[j * k + i].v = btmp;
+        sbstobf16_(&one, &B[j*k+i], &one, &BB[j * k + i], &one);
       }
     }
     for (y = 0; y < 4; y++)
@@ -182,10 +122,12 @@ main (int argc, char *argv[])
               DD[i * m + j] +=
                 float16to32 (AA[k * j + l]) * float16to32 (BB[i + l * n]);
             }
-          if (fabs (CC[i * m + j] - C[i * m + j]) > 1.0)
+          if (!is_close(CC[i * m + j], C[i * m + j], 0.01, 0.001)) {
             ret++;
-          if (fabs (CC[i * m + j] - DD[i * m + j]) > 1.0)
+          }
+          if (!is_close(CC[i * m + j], DD[i * m + j], 0.001, 0.0001)) {
             ret++;
+          }
         }
     }
     free(A);
@@ -211,14 +153,13 @@ main (int argc, char *argv[])
     float *A = (float *)malloc_safe(x * x * sizeof(FLOAT));
     float *B = (float *)malloc_safe(x * sizeof(FLOAT) << l);
     float *C = (float *)malloc_safe(x * sizeof(FLOAT) << l);
-    bfloat16_bits *AA = (bfloat16_bits *)malloc_safe(x * x * sizeof(bfloat16_bits));
-    bfloat16_bits *BB = (bfloat16_bits *)malloc_safe(x * sizeof(bfloat16_bits) << l);
+    bfloat16 *AA = (bfloat16 *)malloc_safe(x * x * sizeof(bfloat16));
+    bfloat16 *BB = (bfloat16 *)malloc_safe(x * sizeof(bfloat16) << l);
     float *DD = (float *)malloc_safe(x * sizeof(FLOAT));
     float *CC = (float *)malloc_safe(x * sizeof(FLOAT) << l);
     if ((A == NULL) || (B == NULL) || (C == NULL) || (AA == NULL) || (BB == NULL) ||
         (DD == NULL) || (CC == NULL))
       return 1;
-    bfloat16 atmp, btmp;
     blasint one = 1;
 
     for (j = 0; j < x; j++)
@@ -226,12 +167,10 @@ main (int argc, char *argv[])
       for (i = 0; i < x; i++)
       {
         A[j * x + i] = ((FLOAT) rand () / (FLOAT) RAND_MAX) + 0.5;
-        sbstobf16_(&one, &A[j*x+i], &one, &atmp, &one);
-        AA[j * x + i].v = atmp;
+        sbstobf16_(&one, &A[j*x+i], &one, &AA[j * x + i], &one);
       }
       B[j << l] = ((FLOAT) rand () / (FLOAT) RAND_MAX) + 0.5;
-      sbstobf16_(&one, &B[j << l], &one, &btmp, &one);
-      BB[j << l].v = btmp;
+      sbstobf16_(&one, &B[j << l], &one, &BB[j << l], &one);
       
       CC[j << l] = C[j << l] = ((FLOAT) rand () / (FLOAT) RAND_MAX) + 0.5;
     }
@@ -262,10 +201,12 @@ main (int argc, char *argv[])
           }
 
       for (j = 0; j < x; j++) {
-        if (fabs (CC[j << l] - C[j << l]) > 1.0)
+        if (!is_close(CC[j << l], C[j << l], 0.01, 0.001)) {
           ret++;
-        if (fabs (CC[j << l] - DD[j]) > 1.0)
+        }
+        if (!is_close(CC[j << l], DD[j], 0.001, 0.0001)) {
           ret++;
+        }
       }
     }
     free(A);

test/test_helpers.h

@@ -0,0 +1,55 @@
+/***************************************************************************
+Copyright (c) 2025 The OpenBLAS Project
+All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+1. Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in
+the documentation and/or other materials provided with the
+distribution.
+3. Neither the name of the OpenBLAS project nor the names of
+its contributors may be used to endorse or promote products
+derived from this software without specific prior written permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBLAS PROJECT OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*****************************************************************************/
+
+#ifndef TEST_HELPERS_H
+#define TEST_HELPERS_H
+#include <stdbool.h>
+
+#include "../common.h"
+
+#if IFLOAT == bfloat16
+static float float16to32(bfloat16 value)
+{
+  blasint one = 1;
+  float result;
+  sbf16tos_(&one, &value, &one, &result, &one);
+  return result;
+}
+#endif
+
+static void *malloc_safe(size_t size) {
+  if (size == 0)
+    return malloc(1);
+  else
+    return malloc(size);
+}
+
+static bool is_close(float a, float b, float rtol, float atol) {
+  return fabs(a - b) <= (atol + rtol*fabs(b));
+}
+
+#endif