[Driver][SYCL] Turn on -fsycl-dead-args-optimization by default (#3004)

Turn on -fsycl-dead-args-optimization by default for -fsycl
compilations.  Update tests to reflect the new behavior

Author: mdtoguchi

clang/lib/Driver/Driver.cpp

@@ -4200,8 +4200,11 @@ class OffloadingActionBuilder final {
             // device objects for future host link. Device libraries should
             // be linked by default to resolve any undefined reference.
             const auto *TC = ToolChains.front();
-            if (TC->getTriple().getSubArch() !=
-                llvm::Triple::SPIRSubArch_fpga) {
+            llvm::Triple TT(TC->getTriple());
+            bool isAOT = TT.getSubArch() == llvm::Triple::SPIRSubArch_fpga ||
+                         TT.getSubArch() == llvm::Triple::SPIRSubArch_gen ||
+                         TT.getSubArch() == llvm::Triple::SPIRSubArch_x86_64;
+            if (TT.getSubArch() != llvm::Triple::SPIRSubArch_fpga) {
               SYCLDeviceLibLinked =
                   addSYCLDeviceLibs(TC, FullSYCLLinkBinaryList, true,
                                     C.getDefaultToolChain()
@@ -4216,11 +4219,26 @@ class OffloadingActionBuilder final {
             else
               FullDeviceLinkAction = DeviceLinkAction;
             auto *PostLinkAction = C.MakeAction<SYCLPostLinkJobAction>(
-                FullDeviceLinkAction, types::TY_LLVM_BC, types::TY_LLVM_BC);
+                FullDeviceLinkAction, types::TY_LLVM_BC,
+                types::TY_Tempfiletable);
+            PostLinkAction->setRTSetsSpecConstants(!isAOT);
+            auto *ExtractIRFilesAction = C.MakeAction<FileTableTformJobAction>(
+                PostLinkAction, types::TY_Tempfilelist, types::TY_Tempfilelist);
+            // single column w/o title fits TY_Tempfilelist format
+            ExtractIRFilesAction->addExtractColumnTform(
+                FileTableTformJobAction::COL_CODE, false /*drop titles*/);
             auto *TranslateAction = C.MakeAction<SPIRVTranslatorJobAction>(
-                PostLinkAction, types::TY_Image);
+                ExtractIRFilesAction, types::TY_Tempfilelist);
+
+            ActionList TformInputs{PostLinkAction, TranslateAction};
+            auto *ReplaceFilesAction = C.MakeAction<FileTableTformJobAction>(
+                TformInputs, types::TY_Tempfiletable, types::TY_Tempfiletable);
+            ReplaceFilesAction->addReplaceColumnTform(
+                FileTableTformJobAction::COL_CODE,
+                FileTableTformJobAction::COL_CODE);
+
             SYCLLinkBinary = C.MakeAction<OffloadWrapperJobAction>(
-                TranslateAction, types::TY_Object);
+                ReplaceFilesAction, types::TY_Object);
           } else {
             auto *Link = C.MakeAction<LinkJobAction>(SYCLLinkBinaryList,
                                                          types::TY_Image);

clang/lib/Driver/ToolChains/Clang.cpp

@@ -695,6 +695,29 @@ static void addCoveragePrefixMapArg(const Driver &D, const ArgList &Args,
   }
 }
 
+/// Simple check to see if the optimization level is at -O2 or higher.
+/// For -fsycl (DPC++) -O2 is the default.
+static bool isSYCLOptimizationO2orHigher(const ArgList &Args) {
+  if (Arg *A = Args.getLastArg(options::OPT_O_Group)) {
+    if (A->getOption().matches(options::OPT_O4) ||
+        A->getOption().matches(options::OPT_Ofast))
+      return true;
+
+    if (A->getOption().matches(options::OPT_O0))
+      return false;
+
+    assert(A->getOption().matches(options::OPT_O) && "Must have a -O flag");
+
+    StringRef S(A->getValue());
+    unsigned OptLevel = 0;
+    if (S.getAsInteger(10, OptLevel))
+      return false;
+    return OptLevel > 1;
+  }
+  // No -O setting seen, default is -O2 for device.
+  return true;
+}
+
 /// Vectorize at all optimization levels greater than 1 except for -Oz.
 /// For -Oz the loop vectorizer is disabled, while the slp vectorizer is
 /// enabled.
@@ -4736,9 +4759,13 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     }
 
     // Turn on Dead Parameter Elimination Optimization with early optimizations
+    // TODO: Enable DAE by default without the Optimization level check in the
+    // driver.  The enabling can be done in CodeGenOpt, and we can pass an
+    // option to explicitly disable/disable here.
     if (!(RawTriple.isAMDGCN()) &&
         Args.hasFlag(options::OPT_fsycl_dead_args_optimization,
-                     options::OPT_fno_sycl_dead_args_optimization, false))
+                     options::OPT_fno_sycl_dead_args_optimization,
+                     isSYCLOptimizationO2orHigher(Args)))
       CmdArgs.push_back("-fenable-sycl-dae");
     bool IsMSVC = AuxT.isWindowsMSVCEnvironment();
     if (IsMSVC) {
@@ -9135,7 +9162,8 @@ void SYCLPostLink::ConstructJob(Compilation &C, const JobAction &JA,
   // Turn on Dead Parameter Elimination Optimization with early optimizations
   if (!(getToolChain().getTriple().isAMDGCN()) &&
       TCArgs.hasFlag(options::OPT_fsycl_dead_args_optimization,
-                     options::OPT_fno_sycl_dead_args_optimization, false))
+                     options::OPT_fno_sycl_dead_args_optimization,
+                     isSYCLOptimizationO2orHigher(TCArgs)))
     addArgs(CmdArgs, TCArgs, {"-emit-param-info"});
   // Enable PI program metadata
   if (getToolChain().getTriple().isNVPTX())

clang/test/Driver/sycl-device-lib.cpp

@@ -128,7 +128,7 @@
 
 /// ###########################################################################
 /// test llvm-link behavior for fno-sycl-device-lib
-// RUN: %clangxx -fsycl -fno-sycl-device-lib=all %s -### 2>&1 \
+// RUN: %clangxx -fsycl -fno-sycl-dead-args-optimization -fno-sycl-device-lib=all %s -### 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=SYCL_LLVM_LINK_NO_DEVICE_LIB
 // SYCL_LLVM_LINK_NO_DEVICE_LIB: clang{{.*}} "-cc1" {{.*}} "-fsycl-is-device"
 // SYCL_LLVM_LINK_NO_DEVICE_LIB-NOT: llvm-link{{.*}}  "-only-needed"

clang/test/Driver/sycl-device-optimizations.cpp

@@ -30,13 +30,21 @@
 // CHECK-NO-SYCL-EARLY-OPTS: "-fno-sycl-early-optimizations"
 
 /// Check that Dead Parameter Elimination Optimization is enabled
-// RUN:   %clang -### -fsycl -fsycl-dead-args-optimization %s 2>&1 \
+// RUN:   %clang -### -fsycl %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-DAE %s
-// RUN:   %clang_cl -### -fsycl -fsycl-dead-args-optimization %s 2>&1 \
+// RUN:   %clang_cl -### -fsycl %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-DAE %s
 // CHECK-DAE: clang{{.*}} "-fenable-sycl-dae"
 // CHECK-DAE: sycl-post-link{{.*}} "-emit-param-info"
 
+/// Check that Dead Parameter Elimination Optimization is disabled
+// RUN:   %clang -### -fsycl -fno-sycl-dead-args-optimization %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-NO-DAE %s
+// RUN:   %clang_cl -### -fsycl -fno-sycl-dead-args-optimization %s 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-NO-DAE %s
+// CHECK-NO-DAE-NOT: clang{{.*}} "-fenable-sycl-dae"
+// CHECK-NO-DAE-NOT: sycl-post-link{{.*}} "-emit-param-info"
+
 // Check "-fgpu-inline-threshold" is passed to the front-end:
 // RUN:   %clang -### -fsycl -fgpu-inline-threshold=100000 %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-THRESH %s

clang/test/Driver/sycl-intelfpga-static-lib.cpp

@@ -10,7 +10,7 @@
 // RUN: llvm-ar cr %t.a %t1_bundle.o
 
 /// Check phases with static lib
-// RUN: %clangxx -target x86_64-unknown-linux-gnu -fsycl -fno-sycl-device-lib=all -fintelfpga %t.a -ccc-print-phases 2>&1 \
+// RUN: %clangxx -target x86_64-unknown-linux-gnu -fsycl -fno-sycl-dead-args-optimization -fno-sycl-device-lib=all -fintelfpga %t.a -ccc-print-phases 2>&1 \
 // RUN:  | FileCheck -check-prefix=CHECK_PHASES %s
 // CHECK_PHASES: 0: input, "[[INPUT:.+\.a]]", object, (host-sycl)
 // CHECK_PHASES: 1: linker, {0}, image, (host-sycl)

clang/test/Driver/sycl-offload.c

@@ -471,9 +471,11 @@
 // CHK-LINK-UB: 1: clang-offload-unbundler, {0}, object
 // CHK-LINK-UB: 2: linker, {1}, image, (device-sycl)
 // CHK-LINK-UB: 3: sycl-post-link, {2}, ir, (device-sycl)
-// CHK-LINK-UB: 4: llvm-spirv, {3}, image, (device-sycl)
-// CHK-LINK-UB: 5: clang-offload-wrapper, {4}, object, (device-sycl)
-// CHK-LINK-UB: 6: offload, "device-sycl (spir64-unknown-unknown)" {5}, object
+// CHK-LINK-UB: 4: file-table-tform, {3}, tempfilelist, (device-sycl)
+// CHK-LINK-UB: 5: llvm-spirv, {4}, tempfilelist, (device-sycl)
+// CHK-LINK-UB: 6: file-table-tform, {3, 5}, tempfiletable, (device-sycl)
+// CHK-LINK-UB: 7: clang-offload-wrapper, {6}, object, (device-sycl)
+// CHK-LINK-UB: 8: offload, "device-sycl (spir64-unknown-unknown)" {7}, object
 
 /// ###########################################################################
 
@@ -487,9 +489,11 @@
 // CHK-LINK: 2: compiler, {1}, ir, (device-sycl)
 // CHK-LINK: 3: linker, {2}, image, (device-sycl)
 // CHK-LINK: 4: sycl-post-link, {3}, ir, (device-sycl)
-// CHK-LINK: 5: llvm-spirv, {4}, image, (device-sycl)
-// CHK-LINK: 6: clang-offload-wrapper, {5}, object, (device-sycl)
-// CHK-LINK: 7: offload, "device-sycl (spir64-unknown-unknown)" {6}, object
+// CHK-LINK: 5: file-table-tform, {4}, tempfilelist, (device-sycl)
+// CHK-LINK: 6: llvm-spirv, {5}, tempfilelist, (device-sycl)
+// CHK-LINK: 7: file-table-tform, {4, 6}, tempfiletable, (device-sycl)
+// CHK-LINK: 8: clang-offload-wrapper, {7}, object, (device-sycl)
+// CHK-LINK: 9: offload, "device-sycl (spir64-unknown-unknown)" {8}, object
 
 /// ###########################################################################
 

sycl/test/scheduler/ReleaseResourcesTest.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx -fsycl -fsycl-targets=%sycl_triple -fsycl-dead-args-optimization -I %sycl_source_dir %s -o %t.out
+// RUN: %clangxx -fsycl -fsycl-targets=%sycl_triple -I %sycl_source_dir %s -o %t.out
 // RUN: %RUN_ON_HOST %t.out
 
 //==------------------- ReleaseResourcesTests.cpp --------------------------==//