Enable the NVPTX LLVM back-end, and add patches fixing bugs.

Use of the NVPTX back-end is only tested on LLVM 3.9 (and hence depends on #19123),
in combination with the CUDAnative.jl package.

deps/llvm.mk

@@ -78,7 +78,11 @@ LLVM_CFLAGS += $(CFLAGS)
 LLVM_CXXFLAGS += $(CXXFLAGS)
 LLVM_CPPFLAGS += $(CPPFLAGS)
 LLVM_LDFLAGS += $(LDFLAGS)
-LLVM_TARGETS := host
+ifeq ($(LLVM_USE_CMAKE),1)
+LLVM_TARGETS := host;NVPTX
+else
+LLVM_TARGETS := host,nvptx
+endif
 LLVM_TARGET_FLAGS := --enable-targets=$(LLVM_TARGETS)
 LLVM_CMAKE += -DLLVM_TARGETS_TO_BUILD:STRING="$(LLVM_TARGETS)" -DCMAKE_BUILD_TYPE="$(LLVM_CMAKE_BUILDTYPE)"
 LLVM_CMAKE += -DLLVM_TOOLS_INSTALL_DIR=$(shell $(JULIAHOME)/contrib/relative_path.sh $(build_prefix) $(build_depsbindir))
@@ -479,6 +483,10 @@ $(eval $(call LLVM_PATCH,llvm-PR22923)) # Remove for 4.0
 $(eval $(call LLVM_PATCH,llvm-r282182)) # Remove for 4.0
 $(eval $(call LLVM_PATCH,llvm-arm-fix-prel31))
 $(eval $(call LLVM_PATCH,llvm-D25865-cmakeshlib))
+# patches for NVPTX
+$(eval $(call LLVM_PATCH,llvm-D9168_argument_alignment)) # Remove for 4.0
+$(eval $(call LLVM_PATCH,llvm-D23597_sdag_names)) # Dep for D24300, remove for 4.0
+$(eval $(call LLVM_PATCH,llvm-D24300_ptx_intrinsics)) # Remove for 4.0
 endif # LLVM_VER
 
 ifeq ($(LLVM_VER),3.7.1)