Merge tag '2.1.5.1'

# By DRC
# Via DRC
* tag '2.1.5.1':
  ChangeLog.md: Document d743a2c1
  OSS-Fuzz: Bail out immediately on decomp failure
  SIMD/x86: Initialize simd_support before every use
  Build: Define THREAD_LOCAL even if !WITH_TURBOJPEG

# Conflicts:
#	CMakeLists.txt

.gitattributes

@@ -3,3 +3,4 @@
 /ci export-ignore
 /.gitattributes export-ignore
 *.ppm binary
+/ChangeLog.md conflict-marker-size=8

CMakeLists.txt

@@ -10,7 +10,7 @@ if(CMAKE_EXECUTABLE_SUFFIX)
 endif()
 
 project(mozjpeg C)
-set(VERSION 4.1.3)
+set(VERSION 4.1.4)
 set(COPYRIGHT_YEAR "1991-2023")
 string(REPLACE "." ";" VERSION_TRIPLET ${VERSION})
 list(GET VERSION_TRIPLET 0 VERSION_MAJOR)
@@ -496,19 +496,17 @@ if(NOT INLINE_WORKS)
 endif()
 message(STATUS "INLINE = ${INLINE} (FORCE_INLINE = ${FORCE_INLINE})")
 
-if(WITH_TURBOJPEG)
+if(MSVC)
-  if(MSVC)
+  set(THREAD_LOCAL "__declspec(thread)")
-    set(THREAD_LOCAL "__declspec(thread)")
+else()
-  else()
+  set(THREAD_LOCAL "__thread")
-    set(THREAD_LOCAL "__thread")
+endif()
-  endif()
+check_c_source_compiles("${THREAD_LOCAL} int i;  int main(void) { i = 0;  return i; }" HAVE_THREAD_LOCAL)
-  check_c_source_compiles("${THREAD_LOCAL} int i;  int main(void) { i = 0;  return i; }" HAVE_THREAD_LOCAL)
+if(HAVE_THREAD_LOCAL)
-  if(HAVE_THREAD_LOCAL)
+  message(STATUS "THREAD_LOCAL = ${THREAD_LOCAL}")
-    message(STATUS "THREAD_LOCAL = ${THREAD_LOCAL}")
+else()
-  else()
+  message(WARNING "Thread-local storage is not available.  The TurboJPEG API library's global error handler will not be thread-safe.")
-    message(WARNING "Thread-local storage is not available.  The TurboJPEG API library's global error handler will not be thread-safe.")
+  unset(THREAD_LOCAL)
-    unset(THREAD_LOCAL)
-  endif()
 endif()
 
 if(UNIX AND NOT APPLE)

ChangeLog.md

@@ -1,3 +1,24 @@
+2.1.5.1
+=======
+
+### Significant changes relative to 2.1.5:
+
+1. The SIMD dispatchers in libjpeg-turbo 2.1.4 and prior stored the list of
+supported SIMD instruction sets in a global variable, which caused an innocuous
+race condition whereby the variable could have been initialized multiple times
+if `jpeg_start_*compress()` was called simultaneously in multiple threads.
+libjpeg-turbo 2.1.5 included an undocumented attempt to fix this race condition
+by making the SIMD support variable thread-local.  However, that caused another
+issue whereby, if `jpeg_start_*compress()` was called in one thread and
+`jpeg_read_*()` or `jpeg_write_*()` was called in a second thread, the SIMD
+support variable was never initialized in the second thread.  On x86 systems,
+this led the second thread to incorrectly assume that AVX2 instructions were
+always available, and when it attempted to use those instructions on older x86
+CPUs that do not support them, an illegal instruction error occurred.  The SIMD
+dispatchers now ensure that the SIMD support variable is initialized before
+dispatching based on its value.
+
+
 2.1.5
 =====
 

fuzz/decompress.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (C)2021 D. R. Commander.  All Rights Reserved.
+ * Copyright (C)2021, 2023 D. R. Commander.  All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -88,7 +88,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
          when using MemorySanitizer. */
       for (i = 0; i < w * h * tjPixelSize[pf]; i++)
         sum += dstBuf[i];
-    }
+    } else
+      goto bailout;
 
     free(dstBuf);
     dstBuf = NULL;

fuzz/decompress_yuv.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (C)2021 D. R. Commander.  All Rights Reserved.
+ * Copyright (C)2021, 2023 D. R. Commander.  All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -90,7 +90,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
          when using MemorySanitizer. */
       for (i = 0; i < w * h * tjPixelSize[pf]; i++)
         sum += dstBuf[i];
-    }
+    } else
+      goto bailout;
 
     free(dstBuf);
     dstBuf = NULL;

simd/i386/jsimd.c

@@ -2,7 +2,7 @@
  * jsimd_i386.c
  *
  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright (C) 2009-2011, 2013-2014, 2016, 2018, 2022, D. R. Commander.
+ * Copyright (C) 2009-2011, 2013-2014, 2016, 2018, 2022-2023, D. R. Commander.
  * Copyright (C) 2015-2016, 2018, 2022, Matthieu Darbois.
  *
  * Based on the x86 SIMD extension for IJG JPEG library,
@@ -158,6 +158,9 @@ jsimd_rgb_ycc_convert(j_compress_ptr cinfo, JSAMPARRAY input_buf,
   void (*sse2fct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
   void (*mmxfct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->in_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_extrgb_ycc_convert_avx2;
@@ -217,6 +220,9 @@ jsimd_rgb_gray_convert(j_compress_ptr cinfo, JSAMPARRAY input_buf,
   void (*sse2fct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
   void (*mmxfct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->in_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_extrgb_gray_convert_avx2;
@@ -276,6 +282,9 @@ jsimd_ycc_rgb_convert(j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
   void (*sse2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY, int);
   void (*mmxfct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY, int);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->out_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_ycc_extrgb_convert_avx2;
@@ -379,6 +388,9 @@ GLOBAL(void)
 jsimd_h2v2_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr,
                       JSAMPARRAY input_data, JSAMPARRAY output_data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v2_downsample_avx2(cinfo->image_width, cinfo->max_v_samp_factor,
                                compptr->v_samp_factor,
@@ -399,6 +411,9 @@ GLOBAL(void)
 jsimd_h2v1_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr,
                       JSAMPARRAY input_data, JSAMPARRAY output_data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v1_downsample_avx2(cinfo->image_width, cinfo->max_v_samp_factor,
                                compptr->v_samp_factor,
@@ -461,6 +476,9 @@ GLOBAL(void)
 jsimd_h2v2_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                     JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v2_upsample_avx2(cinfo->max_v_samp_factor, cinfo->output_width,
                              input_data, output_data_ptr);
@@ -476,6 +494,9 @@ GLOBAL(void)
 jsimd_h2v1_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                     JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v1_upsample_avx2(cinfo->max_v_samp_factor, cinfo->output_width,
                              input_data, output_data_ptr);
@@ -537,6 +558,9 @@ GLOBAL(void)
 jsimd_h2v2_fancy_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                           JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v2_fancy_upsample_avx2(cinfo->max_v_samp_factor,
                                    compptr->downsampled_width, input_data,
@@ -555,6 +579,9 @@ GLOBAL(void)
 jsimd_h2v1_fancy_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                           JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v1_fancy_upsample_avx2(cinfo->max_v_samp_factor,
                                    compptr->downsampled_width, input_data,
@@ -623,6 +650,9 @@ jsimd_h2v2_merged_upsample(j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
   void (*sse2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
   void (*mmxfct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->out_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_h2v2_extrgb_merged_upsample_avx2;
@@ -681,6 +711,9 @@ jsimd_h2v1_merged_upsample(j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
   void (*sse2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
   void (*mmxfct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->out_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_h2v1_extrgb_merged_upsample_avx2;
@@ -785,6 +818,9 @@ GLOBAL(void)
 jsimd_convsamp(JSAMPARRAY sample_data, JDIMENSION start_col,
                DCTELEM *workspace)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_convsamp_avx2(sample_data, start_col, workspace);
   else if (simd_support & JSIMD_SSE2)
@@ -797,6 +833,9 @@ GLOBAL(void)
 jsimd_convsamp_float(JSAMPARRAY sample_data, JDIMENSION start_col,
                      FAST_FLOAT *workspace)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_SSE2)
     jsimd_convsamp_float_sse2(sample_data, start_col, workspace);
   else if (simd_support & JSIMD_SSE)
@@ -867,6 +906,9 @@ jsimd_can_fdct_float(void)
 GLOBAL(void)
 jsimd_fdct_islow(DCTELEM *data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_fdct_islow_avx2(data);
   else if (simd_support & JSIMD_SSE2)
@@ -878,6 +920,9 @@ jsimd_fdct_islow(DCTELEM *data)
 GLOBAL(void)
 jsimd_fdct_ifast(DCTELEM *data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if ((simd_support & JSIMD_SSE2) && IS_ALIGNED_SSE(jconst_fdct_islow_sse2))
     jsimd_fdct_ifast_sse2(data);
   else
@@ -887,6 +932,9 @@ jsimd_fdct_ifast(DCTELEM *data)
 GLOBAL(void)
 jsimd_fdct_float(FAST_FLOAT *data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if ((simd_support & JSIMD_SSE) && IS_ALIGNED_SSE(jconst_fdct_float_sse))
     jsimd_fdct_float_sse(data);
   else if (simd_support & JSIMD_3DNOW)
@@ -942,6 +990,9 @@ jsimd_can_quantize_float(void)
 GLOBAL(void)
 jsimd_quantize(JCOEFPTR coef_block, DCTELEM *divisors, DCTELEM *workspace)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_quantize_avx2(coef_block, divisors, workspace);
   else if (simd_support & JSIMD_SSE2)
@@ -954,6 +1005,9 @@ GLOBAL(void)
 jsimd_quantize_float(JCOEFPTR coef_block, FAST_FLOAT *divisors,
                      FAST_FLOAT *workspace)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_SSE2)
     jsimd_quantize_float_sse2(coef_block, divisors, workspace);
   else if (simd_support & JSIMD_SSE)
@@ -1017,6 +1071,9 @@ jsimd_idct_2x2(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                JCOEFPTR coef_block, JSAMPARRAY output_buf,
                JDIMENSION output_col)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if ((simd_support & JSIMD_SSE2) && IS_ALIGNED_SSE(jconst_idct_red_sse2))
     jsimd_idct_2x2_sse2(compptr->dct_table, coef_block, output_buf,
                         output_col);
@@ -1029,6 +1086,9 @@ jsimd_idct_4x4(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                JCOEFPTR coef_block, JSAMPARRAY output_buf,
                JDIMENSION output_col)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if ((simd_support & JSIMD_SSE2) && IS_ALIGNED_SSE(jconst_idct_red_sse2))
     jsimd_idct_4x4_sse2(compptr->dct_table, coef_block, output_buf,
                         output_col);
@@ -1123,6 +1183,9 @@ jsimd_idct_islow(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                  JCOEFPTR coef_block, JSAMPARRAY output_buf,
                  JDIMENSION output_col)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_idct_islow_avx2(compptr->dct_table, coef_block, output_buf,
                           output_col);
@@ -1139,6 +1202,9 @@ jsimd_idct_ifast(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                  JCOEFPTR coef_block, JSAMPARRAY output_buf,
                  JDIMENSION output_col)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if ((simd_support & JSIMD_SSE2) && IS_ALIGNED_SSE(jconst_idct_ifast_sse2))
     jsimd_idct_ifast_sse2(compptr->dct_table, coef_block, output_buf,
                           output_col);
@@ -1152,6 +1218,9 @@ jsimd_idct_float(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                  JCOEFPTR coef_block, JSAMPARRAY output_buf,
                  JDIMENSION output_col)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if ((simd_support & JSIMD_SSE2) && IS_ALIGNED_SSE(jconst_idct_float_sse2))
     jsimd_idct_float_sse2(compptr->dct_table, coef_block, output_buf,
                           output_col);

simd/x86_64/jsimd.c

@@ -2,7 +2,7 @@
  * jsimd_x86_64.c
  *
  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright (C) 2009-2011, 2014, 2016, 2018, 2022, D. R. Commander.
+ * Copyright (C) 2009-2011, 2014, 2016, 2018, 2022-2023, D. R. Commander.
  * Copyright (C) 2015-2016, 2018, 2022, Matthieu Darbois.
  *
  * Based on the x86 SIMD extension for IJG JPEG library,
@@ -145,6 +145,9 @@ jsimd_rgb_ycc_convert(j_compress_ptr cinfo, JSAMPARRAY input_buf,
   void (*avx2fct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
   void (*sse2fct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->in_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_extrgb_ycc_convert_avx2;
@@ -194,6 +197,9 @@ jsimd_rgb_gray_convert(j_compress_ptr cinfo, JSAMPARRAY input_buf,
   void (*avx2fct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
   void (*sse2fct) (JDIMENSION, JSAMPARRAY, JSAMPIMAGE, JDIMENSION, int);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->in_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_extrgb_gray_convert_avx2;
@@ -243,6 +249,9 @@ jsimd_ycc_rgb_convert(j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
   void (*avx2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY, int);
   void (*sse2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY, int);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->out_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_ycc_extrgb_convert_avx2;
@@ -333,6 +342,9 @@ GLOBAL(void)
 jsimd_h2v2_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr,
                       JSAMPARRAY input_data, JSAMPARRAY output_data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v2_downsample_avx2(cinfo->image_width, cinfo->max_v_samp_factor,
                                compptr->v_samp_factor,
@@ -349,6 +361,9 @@ GLOBAL(void)
 jsimd_h2v1_downsample(j_compress_ptr cinfo, jpeg_component_info *compptr,
                       JSAMPARRAY input_data, JSAMPARRAY output_data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v1_downsample_avx2(cinfo->image_width, cinfo->max_v_samp_factor,
                                compptr->v_samp_factor,
@@ -403,6 +418,9 @@ GLOBAL(void)
 jsimd_h2v2_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                     JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v2_upsample_avx2(cinfo->max_v_samp_factor, cinfo->output_width,
                              input_data, output_data_ptr);
@@ -415,6 +433,9 @@ GLOBAL(void)
 jsimd_h2v1_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                     JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v1_upsample_avx2(cinfo->max_v_samp_factor, cinfo->output_width,
                              input_data, output_data_ptr);
@@ -469,6 +490,9 @@ GLOBAL(void)
 jsimd_h2v2_fancy_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                           JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v2_fancy_upsample_avx2(cinfo->max_v_samp_factor,
                                    compptr->downsampled_width, input_data,
@@ -483,6 +507,9 @@ GLOBAL(void)
 jsimd_h2v1_fancy_upsample(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                           JSAMPARRAY input_data, JSAMPARRAY *output_data_ptr)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_h2v1_fancy_upsample_avx2(cinfo->max_v_samp_factor,
                                    compptr->downsampled_width, input_data,
@@ -542,6 +569,9 @@ jsimd_h2v2_merged_upsample(j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
   void (*avx2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
   void (*sse2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->out_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_h2v2_extrgb_merged_upsample_avx2;
@@ -590,6 +620,9 @@ jsimd_h2v1_merged_upsample(j_decompress_ptr cinfo, JSAMPIMAGE input_buf,
   void (*avx2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
   void (*sse2fct) (JDIMENSION, JSAMPIMAGE, JDIMENSION, JSAMPARRAY);
 
+  if (simd_support == ~0U)
+    init_simd();
+
   switch (cinfo->out_color_space) {
   case JCS_EXT_RGB:
     avx2fct = jsimd_h2v1_extrgb_merged_upsample_avx2;
@@ -679,6 +712,9 @@ GLOBAL(void)
 jsimd_convsamp(JSAMPARRAY sample_data, JDIMENSION start_col,
                DCTELEM *workspace)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_convsamp_avx2(sample_data, start_col, workspace);
   else
@@ -748,6 +784,9 @@ jsimd_can_fdct_float(void)
 GLOBAL(void)
 jsimd_fdct_islow(DCTELEM *data)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_fdct_islow_avx2(data);
   else
@@ -809,6 +848,9 @@ jsimd_can_quantize_float(void)
 GLOBAL(void)
 jsimd_quantize(JCOEFPTR coef_block, DCTELEM *divisors, DCTELEM *workspace)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_quantize_avx2(coef_block, divisors, workspace);
   else
@@ -963,6 +1005,9 @@ jsimd_idct_islow(j_decompress_ptr cinfo, jpeg_component_info *compptr,
                  JCOEFPTR coef_block, JSAMPARRAY output_buf,
                  JDIMENSION output_col)
 {
+  if (simd_support == ~0U)
+    init_simd();
+
   if (simd_support & JSIMD_AVX2)
     jsimd_idct_islow_avx2(compptr->dct_table, coef_block, output_buf,
                           output_col);