[PATCH] D102839: [RISCV][Clang] Add -mno-div option to disable hardware int division

[ksyx via Phabricator via cfe-commits]

ksyx updated this revision to Diff 348525.
ksyx added a comment.

split `Zmmul` implementation and `-mno-div` implementation


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102839/new/

https://reviews.llvm.org/D102839

Files:
  clang/include/clang/Driver/Options.td
  clang/lib/Driver/ToolChains/Arch/RISCV.cpp
  clang/test/Driver/riscv-no-div.c


Index: clang/test/Driver/riscv-no-div.c
===================================================================
--- /dev/null
+++ clang/test/Driver/riscv-no-div.c
@@ -0,0 +1,30 @@
+// RUN: %clang -target riscv32-unknown-elf %s -mno-div -S -o - 2>&1 \
+// RUN:   | not FileCheck -check-prefix=CHECK-DIV %s
+
+// RUN: %clang -target riscv64-unknown-elf %s -mno-div -S -o - 2>&1 \
+// RUN:   | not FileCheck -check-prefix=CHECK-DIV %s
+
+// RUN: %clang -target riscv32-unknown-elf %s -mno-div -S -o - 2>&1 \
+// RUN:   | not FileCheck -check-prefix=CHECK-REM %s
+
+// RUN: %clang -target riscv64-unknown-elf %s -mno-div -S -o - 2>&1 \
+// RUN:   | not FileCheck -check-prefix=CHECK-REM %s
+
+// RUN: %clang -target riscv32-unknown-elf %s -mno-div -S -o - 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-MUL %s
+
+// RUN: %clang -target riscv64-unknown-elf %s -mno-div -S -o - 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-MUL %s
+
+// RUN: %clang -target riscv32-unknown-elf %s -S -o - 2>&1 \
+// RUN:   | FileCheck -check-prefixes=CHECK-MUL,CHECK-DIV,CHECK-REM %s
+
+// RUN: %clang -target riscv64-unknown-elf %s -S -o - 2>&1 \
+// RUN:   | FileCheck -check-prefixes=CHECK-MUL,CHECK-DIV,CHECK-REM %s
+
+int foo(int x, int y) {
+  // CHECK-DIV: div{{w?}} a{{[0-9]}}, a{{[0-9]}}, a{{[0-9]}}
+  // CHECK-REM: rem{{w?}} a{{[0-9]}}, a{{[0-9]}}, a{{[0-9]}}
+  // CHECK-MUL: mul{{w?}} a{{[0-9]}}, a{{[0-9]}}, a{{[0-9]}}
+  return (x / y) * (x % y);
+}
Index: clang/lib/Driver/ToolChains/Arch/RISCV.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Arch/RISCV.cpp
+++ clang/lib/Driver/ToolChains/Arch/RISCV.cpp
@@ -572,6 +572,15 @@
   // Now add any that the user explicitly requested on the command line,
   // which may override the defaults.
   handleTargetFeaturesGroup(Args, Features, options::OPT_m_riscv_Features_Group);
+
+  bool noDiv = Args.hasFlag(options::OPT_mno_div, options::OPT_mdiv, false);
+  for (auto &Feature : Features) {
+    if (noDiv && (Feature == "+m" || Feature == "-div")) {
+      Feature = "+experimental-zmmul";
+    } else if (Feature == "+div") {
+      Feature = "+m";
+    }
+  }
 }
 
 StringRef riscv::getRISCVABI(const ArgList &Args, const llvm::Triple &Triple) {
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -3146,6 +3146,10 @@
   HelpText<"Enable using library calls for save and restore">;
 def mno_save_restore : Flag<["-"], "mno-save-restore">, Group<m_riscv_Features_Group>,
   HelpText<"Disable using library calls for save and restore">;
+def mno_div : Flag<["-"], "mno-div">, Group<m_riscv_Features_Group>,
+  HelpText<"Disable integer division instructions in M extension">;
+def mdiv : Flag<["-"], "mdiv">, Group<m_riscv_Features_Group>,
+  HelpText<"Enable integer division instructions in M extension">;
 def mcmodel_EQ_medlow : Flag<["-"], "mcmodel=medlow">, Group<m_riscv_Features_Group>,
   Flags<[CC1Option]>, Alias<mcmodel_EQ>, AliasArgs<["small"]>,
   HelpText<"Equivalent to -mcmodel=small, compatible with RISC-V gcc.">;


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