commit 624110b90daf2876058ce9bb1207d69612bd9ab9
author Brad King <brad.king@kitware.com> Thu Jun 10 08:56:59 2021 -0400
committer Brad King <brad.king@kitware.com> Thu Jun 10 12:39:00 2021 -0400
tree 33183d094f5c6358508b81ad1a2c2af5e35aa0a0
parent b6faa5e2df22fecac877dc866294e8b5a36ab03a

FindBLAS: Revert "Do not statically link against iomp5 ... Intel MKL"

Since commit 20ab504591 (FindBLAS: Do not statically link against iomp5
in the case of Intel MKL, 2021-04-11), we no longer find MKL's BLAS when
using the GNU compiler because FindOpenMP chooses libgomp instead of
libiomp5, and mkl_intel_thread depends on the latter.  Revert the change
for now.  A new approach will be needed to solve the original problem.

Issue: #21811

Modules/FindBLAS.cmake

diff --git a/Modules/FindBLAS.cmake b/Modules/FindBLAS.cmake
index 0f8360a..826a9c2 100644
--- a/Modules/FindBLAS.cmake
+++ b/Modules/FindBLAS.cmake
@@ -337,21 +337,12 @@
         if(CMAKE_Fortran_COMPILER_LOADED AND CMAKE_Fortran_COMPILER_ID STREQUAL "GNU" AND NOT APPLE)
             set(BLAS_mkl_INTFACE "gf")
             set(BLAS_mkl_THREADING "gnu")
+            set(BLAS_mkl_OMP "gomp")
         else()
             set(BLAS_mkl_INTFACE "intel")
             set(BLAS_mkl_THREADING "intel")
+            set(BLAS_mkl_OMP "iomp5")
         endif()
-
-        foreach(lang IN ITEMS C CXX Fortran)
-          if(CMAKE_${lang}_COMPILER_LOADED)
-            find_package(OpenMP COMPONENTS ${lang})
-            if(${OpenMP_${lang}_FOUND})
-              set(BLAS_mkl_OMP ${OpenMP_${lang}_LIBRARIES})
-              break()
-            endif()
-          endif()
-        endforeach()
-
         set(BLAS_mkl_LM "-lm")
         set(BLAS_mkl_LDL "-ldl")
       endif()
@@ -416,7 +407,7 @@
 
             # mkl >= 10.3
             list(APPEND BLAS_SEARCH_LIBS
-              "${BLAS_mkl_START_GROUP} mkl_blas95 mkl_${BLAS_mkl_INTFACE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP}")
+              "${BLAS_mkl_START_GROUP} mkl_blas95 mkl_${BLAS_mkl_INTFACE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP} ${BLAS_mkl_OMP}")
           endif()
           if(BLA_VENDOR MATCHES "^Intel10_64i?lp$" OR BLA_VENDOR STREQUAL "All")
             # old version
@@ -425,7 +416,7 @@
 
             # mkl >= 10.3
             list(APPEND BLAS_SEARCH_LIBS
-              "${BLAS_mkl_START_GROUP} mkl_blas95_${BLAS_mkl_ILP_MODE} mkl_${BLAS_mkl_INTFACE}_${BLAS_mkl_ILP_MODE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP}")
+              "${BLAS_mkl_START_GROUP} mkl_blas95_${BLAS_mkl_ILP_MODE} mkl_${BLAS_mkl_INTFACE}_${BLAS_mkl_ILP_MODE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP} ${BLAS_mkl_OMP}")
           endif()
           if(BLA_VENDOR MATCHES "^Intel10_64i?lp_seq$" OR BLA_VENDOR STREQUAL "All")
             list(APPEND BLAS_SEARCH_LIBS
@@ -481,7 +472,7 @@
 
             # mkl >= 10.3
             list(APPEND BLAS_SEARCH_LIBS
-              "${BLAS_mkl_START_GROUP} mkl_${BLAS_mkl_INTFACE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP}")
+              "${BLAS_mkl_START_GROUP} mkl_${BLAS_mkl_INTFACE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP} ${BLAS_mkl_OMP}")
           endif()
           if(BLA_VENDOR MATCHES "^Intel10_64i?lp$" OR BLA_VENDOR STREQUAL "All")
             # old version
@@ -490,7 +481,7 @@
 
             # mkl >= 10.3
             list(APPEND BLAS_SEARCH_LIBS
-              "${BLAS_mkl_START_GROUP} mkl_${BLAS_mkl_INTFACE}_${BLAS_mkl_ILP_MODE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP}")
+              "${BLAS_mkl_START_GROUP} mkl_${BLAS_mkl_INTFACE}_${BLAS_mkl_ILP_MODE} mkl_${BLAS_mkl_THREADING}_thread mkl_core ${BLAS_mkl_END_GROUP} ${BLAS_mkl_OMP}")
           endif()
           if(BLA_VENDOR MATCHES "^Intel10_64i?lp_seq$" OR BLA_VENDOR STREQUAL "All")
             list(APPEND BLAS_SEARCH_LIBS
@@ -553,7 +544,7 @@
             ${BLAS_mkl_SEARCH_SYMBOL}
             ""
             "${SEARCH_LIBS}"
-            "${BLAS_mkl_OMP};${CMAKE_THREAD_LIBS_INIT};${BLAS_mkl_LM};${BLAS_mkl_LDL}"
+            "${CMAKE_THREAD_LIBS_INIT};${BLAS_mkl_LM};${BLAS_mkl_LDL}"
             "${BLAS_mkl_MKLROOT}"
             "${BLAS_mkl_LIB_PATH_SUFFIXES}"
             )