diff --git a/config/c-compiler.m4 b/config/c-compiler.m4
index 8534cc54c13..3712e81e38c 100644
--- a/config/c-compiler.m4
+++ b/config/c-compiler.m4
@@ -553,16 +553,20 @@ fi])# PGAC_HAVE_GCC__ATOMIC_INT64_CAS
 # the other ones are, on x86-64 platforms)
 #
 # If the intrinsics are supported, sets pgac_sse42_crc32_intrinsics.
+#
+# To detect the case where the compiler knows the function but library support
+# is missing, we must link not just compile, and store the results in global
+# variables so the compiler doesn't optimize away the call.
 AC_DEFUN([PGAC_SSE42_CRC32_INTRINSICS],
 [define([Ac_cachevar], [AS_TR_SH([pgac_cv_sse42_crc32_intrinsics])])dnl
 AC_CACHE_CHECK([for _mm_crc32_u8 and _mm_crc32_u32], [Ac_cachevar],
 [AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <nmmintrin.h>
+    unsigned int crc;
     #if defined(__has_attribute) && __has_attribute (target)
     __attribute__((target("sse4.2")))
     #endif
     static int crc32_sse42_test(void)
     {
-      unsigned int crc = 0;
       crc = _mm_crc32_u8(crc, 0);
       crc = _mm_crc32_u32(crc, 0);
       /* return computed value, to prevent the above being optimized away */
@@ -593,9 +597,9 @@ AC_DEFUN([PGAC_ARMV8_CRC32C_INTRINSICS],
 AC_CACHE_CHECK([for __crc32cb, __crc32ch, __crc32cw, and __crc32cd with CFLAGS=$1], [Ac_cachevar],
 [pgac_save_CFLAGS=$CFLAGS
 CFLAGS="$pgac_save_CFLAGS $1"
-AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <arm_acle.h>],
-  [unsigned int crc = 0;
-   crc = __crc32cb(crc, 0);
+AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <arm_acle.h>
+unsigned int crc;],
+  [crc = __crc32cb(crc, 0);
    crc = __crc32ch(crc, 0);
    crc = __crc32cw(crc, 0);
    crc = __crc32cd(crc, 0);
@@ -628,9 +632,8 @@ AC_DEFUN([PGAC_LOONGARCH_CRC32C_INTRINSICS],
 AC_CACHE_CHECK(
   [for __builtin_loongarch_crcc_w_b_w, __builtin_loongarch_crcc_w_h_w, __builtin_loongarch_crcc_w_w_w and __builtin_loongarch_crcc_w_d_w],
   [Ac_cachevar],
-[AC_LINK_IFELSE([AC_LANG_PROGRAM([],
-  [unsigned int crc = 0;
-   crc = __builtin_loongarch_crcc_w_b_w(0, crc);
+[AC_LINK_IFELSE([AC_LANG_PROGRAM([unsigned int crc;],
+  [crc = __builtin_loongarch_crcc_w_b_w(0, crc);
    crc = __builtin_loongarch_crcc_w_h_w(0, crc);
    crc = __builtin_loongarch_crcc_w_w_w(0, crc);
    crc = __builtin_loongarch_crcc_w_d_w(0, crc);
@@ -680,22 +683,23 @@ undefine([Ac_cachevar])dnl
 AC_DEFUN([PGAC_AVX512_POPCNT_INTRINSICS],
 [define([Ac_cachevar], [AS_TR_SH([pgac_cv_avx512_popcnt_intrinsics])])dnl
 AC_CACHE_CHECK([for _mm512_popcnt_epi64], [Ac_cachevar],
-[AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <immintrin.h>
+[AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <immintrin.h>
     #include <stdint.h>
+    char buf[sizeof(__m512i)];
+
     #if defined(__has_attribute) && __has_attribute (target)
     __attribute__((target("avx512vpopcntdq,avx512bw")))
     #endif
     static int popcount_test(void)
     {
-      const char buf@<:@sizeof(__m512i)@:>@;
       int64_t popcnt = 0;
       __m512i accum = _mm512_setzero_si512();
-      const __m512i val = _mm512_maskz_loadu_epi8((__mmask64) 0xf0f0f0f0f0f0f0f0, (const __m512i *) buf);
-      const __m512i cnt = _mm512_popcnt_epi64(val);
+      __m512i val = _mm512_maskz_loadu_epi8((__mmask64) 0xf0f0f0f0f0f0f0f0, (const __m512i *) buf);
+      __m512i cnt = _mm512_popcnt_epi64(val);
       accum = _mm512_add_epi64(accum, cnt);
       popcnt = _mm512_reduce_add_epi64(accum);
       return (int) popcnt;
-    }],
+    }]],
   [return popcount_test();])],
   [Ac_cachevar=yes],
   [Ac_cachevar=no])])
diff --git a/configure b/configure
index 559f535f5cd..fac1e9a4e39 100755
--- a/configure
+++ b/configure
@@ -17334,16 +17334,17 @@ else
 /* end confdefs.h.  */
 #include <immintrin.h>
     #include <stdint.h>
+    char buf[sizeof(__m512i)];
+
     #if defined(__has_attribute) && __has_attribute (target)
     __attribute__((target("avx512vpopcntdq,avx512bw")))
     #endif
     static int popcount_test(void)
     {
-      const char buf[sizeof(__m512i)];
       int64_t popcnt = 0;
       __m512i accum = _mm512_setzero_si512();
-      const __m512i val = _mm512_maskz_loadu_epi8((__mmask64) 0xf0f0f0f0f0f0f0f0, (const __m512i *) buf);
-      const __m512i cnt = _mm512_popcnt_epi64(val);
+      __m512i val = _mm512_maskz_loadu_epi8((__mmask64) 0xf0f0f0f0f0f0f0f0, (const __m512i *) buf);
+      __m512i cnt = _mm512_popcnt_epi64(val);
       accum = _mm512_add_epi64(accum, cnt);
       popcnt = _mm512_reduce_add_epi64(accum);
       return (int) popcnt;
@@ -17387,12 +17388,12 @@ else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <nmmintrin.h>
+    unsigned int crc;
     #if defined(__has_attribute) && __has_attribute (target)
     __attribute__((target("sse4.2")))
     #endif
     static int crc32_sse42_test(void)
     {
-      unsigned int crc = 0;
       crc = _mm_crc32_u8(crc, 0);
       crc = _mm_crc32_u32(crc, 0);
       /* return computed value, to prevent the above being optimized away */
@@ -17459,11 +17460,11 @@ CFLAGS="$pgac_save_CFLAGS "
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <arm_acle.h>
+unsigned int crc;
 int
 main ()
 {
-unsigned int crc = 0;
-   crc = __crc32cb(crc, 0);
+crc = __crc32cb(crc, 0);
    crc = __crc32ch(crc, 0);
    crc = __crc32cw(crc, 0);
    crc = __crc32cd(crc, 0);
@@ -17500,11 +17501,11 @@ CFLAGS="$pgac_save_CFLAGS -march=armv8-a+crc+simd"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <arm_acle.h>
+unsigned int crc;
 int
 main ()
 {
-unsigned int crc = 0;
-   crc = __crc32cb(crc, 0);
+crc = __crc32cb(crc, 0);
    crc = __crc32ch(crc, 0);
    crc = __crc32cw(crc, 0);
    crc = __crc32cd(crc, 0);
@@ -17541,11 +17542,11 @@ CFLAGS="$pgac_save_CFLAGS -march=armv8-a+crc"
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <arm_acle.h>
+unsigned int crc;
 int
 main ()
 {
-unsigned int crc = 0;
-   crc = __crc32cb(crc, 0);
+crc = __crc32cb(crc, 0);
    crc = __crc32ch(crc, 0);
    crc = __crc32cw(crc, 0);
    crc = __crc32cd(crc, 0);
@@ -17585,12 +17586,11 @@ if ${pgac_cv_loongarch_crc32c_intrinsics+:} false; then :
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-
+unsigned int crc;
 int
 main ()
 {
-unsigned int crc = 0;
-   crc = __builtin_loongarch_crcc_w_b_w(0, crc);
+crc = __builtin_loongarch_crcc_w_b_w(0, crc);
    crc = __builtin_loongarch_crcc_w_h_w(0, crc);
    crc = __builtin_loongarch_crcc_w_w_w(0, crc);
    crc = __builtin_loongarch_crcc_w_d_w(0, crc);
diff --git a/meson.build b/meson.build
index b6daa5b7040..01c0f11b862 100644
--- a/meson.build
+++ b/meson.build
@@ -2259,17 +2259,17 @@ if host_cpu == 'x86_64'
   prog = '''
 #include <immintrin.h>
 #include <stdint.h>
+char buf[sizeof(__m512i)];
 
 #if defined(__has_attribute) && __has_attribute (target)
 __attribute__((target("avx512vpopcntdq,avx512bw")))
 #endif
 int main(void)
 {
-    const char buf[sizeof(__m512i)];
     int64_t popcnt = 0;
     __m512i accum = _mm512_setzero_si512();
-    const __m512i val = _mm512_maskz_loadu_epi8((__mmask64) 0xf0f0f0f0f0f0f0f0, (const __m512i *) buf);
-    const __m512i cnt = _mm512_popcnt_epi64(val);
+    __m512i val = _mm512_maskz_loadu_epi8((__mmask64) 0xf0f0f0f0f0f0f0f0, (const __m512i *) buf);
+    __m512i cnt = _mm512_popcnt_epi64(val);
     accum = _mm512_add_epi64(accum, cnt);
     popcnt = _mm512_reduce_add_epi64(accum);
     /* return computed value, to prevent the above being optimized away */
@@ -2317,13 +2317,13 @@ if host_cpu == 'x86' or host_cpu == 'x86_64'
 
     prog = '''
 #include <nmmintrin.h>
+unsigned int crc;
 
 #if defined(__has_attribute) && __has_attribute (target)
 __attribute__((target("sse4.2")))
 #endif
 int main(void)
 {
-    unsigned int crc = 0;
     crc = _mm_crc32_u8(crc, 0);
     crc = _mm_crc32_u32(crc, 0);
     /* return computed value, to prevent the above being optimized away */
@@ -2352,10 +2352,10 @@ elif host_cpu == 'arm' or host_cpu == 'aarch64'
 
   prog = '''
 #include <arm_acle.h>
+unsigned int crc;
 
 int main(void)
 {
-    unsigned int crc = 0;
     crc = __crc32cb(crc, 0);
     crc = __crc32ch(crc, 0);
     crc = __crc32cw(crc, 0);
@@ -2390,9 +2390,10 @@ int main(void)
 elif host_cpu == 'loongarch64'
 
   prog = '''
+unsigned int crc;
+
 int main(void)
 {
-    unsigned int crc = 0;
     crc = __builtin_loongarch_crcc_w_b_w(0, crc);
     crc = __builtin_loongarch_crcc_w_h_w(0, crc);
     crc = __builtin_loongarch_crcc_w_w_w(0, crc);