[WebAssembly] Trapping fptoint builtins and intrinsics

Summary:
The WebAssembly backend lowers fptoint instructions to a code sequence
that checks for overflow to avoid traps because fptoint is supposed to
be speculatable. These new builtins and intrinsics give users a way to
depend on the trapping semantics of the underlying instructions and
avoid the extra code generated normally.

Patch by coffee and tlively.

Reviewers: aheejin

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D68902

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374856 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 78 insertions, 0 deletions

diff --git a/include/clang/Basic/BuiltinsWebAssembly.def b/include/clang/Basic/BuiltinsWebAssembly.def
index 7e80e91c56..7fed9d2e43 100644
--- a/include/clang/Basic/BuiltinsWebAssembly.def
+++ b/include/clang/Basic/BuiltinsWebAssembly.def
@@ -49,6 +49,16 @@ BUILTIN(__builtin_wasm_atomic_wait_i32, "ii*iLLi", "n")
 BUILTIN(__builtin_wasm_atomic_wait_i64, "iLLi*LLiLLi", "n")
 BUILTIN(__builtin_wasm_atomic_notify, "Uii*Ui", "n")
 
+// Trapping fp-to-int conversions
+BUILTIN(__builtin_wasm_trunc_s_i32_f32, "if", "nc")
+BUILTIN(__builtin_wasm_trunc_u_i32_f32, "if", "nc")
+BUILTIN(__builtin_wasm_trunc_s_i32_f64, "id", "nc")
+BUILTIN(__builtin_wasm_trunc_u_i32_f64, "id", "nc")
+BUILTIN(__builtin_wasm_trunc_s_i64_f32, "LLif", "nc")
+BUILTIN(__builtin_wasm_trunc_u_i64_f32, "LLif", "nc")
+BUILTIN(__builtin_wasm_trunc_s_i64_f64, "LLid", "nc")
+BUILTIN(__builtin_wasm_trunc_u_i64_f64, "LLid", "nc")
+
 // Saturating fp-to-int conversions
 TARGET_BUILTIN(__builtin_wasm_trunc_saturate_s_i32_f32, "if", "nc", "nontrapping-fptoint")
 TARGET_BUILTIN(__builtin_wasm_trunc_saturate_u_i32_f32, "if", "nc", "nontrapping-fptoint")
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 2ccd16da25..e75966c028 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -14020,6 +14020,26 @@ Value *CodeGenFunction::EmitWebAssemblyBuiltinExpr(unsigned BuiltinID,
     Function *Callee = CGM.getIntrinsic(Intrinsic::wasm_atomic_notify);
     return Builder.CreateCall(Callee, {Addr, Count});
   }
+  case WebAssembly::BI__builtin_wasm_trunc_s_i32_f32:
+  case WebAssembly::BI__builtin_wasm_trunc_s_i32_f64:
+  case WebAssembly::BI__builtin_wasm_trunc_s_i64_f32:
+  case WebAssembly::BI__builtin_wasm_trunc_s_i64_f64: {
+    Value *Src = EmitScalarExpr(E->getArg(0));
+    llvm::Type *ResT = ConvertType(E->getType());
+    Function *Callee =
+        CGM.getIntrinsic(Intrinsic::wasm_trunc_signed, {ResT, Src->getType()});
+    return Builder.CreateCall(Callee, {Src});
+  }
+  case WebAssembly::BI__builtin_wasm_trunc_u_i32_f32:
+  case WebAssembly::BI__builtin_wasm_trunc_u_i32_f64:
+  case WebAssembly::BI__builtin_wasm_trunc_u_i64_f32:
+  case WebAssembly::BI__builtin_wasm_trunc_u_i64_f64: {
+    Value *Src = EmitScalarExpr(E->getArg(0));
+    llvm::Type *ResT = ConvertType(E->getType());
+    Function *Callee = CGM.getIntrinsic(Intrinsic::wasm_trunc_unsigned,
+                                        {ResT, Src->getType()});
+    return Builder.CreateCall(Callee, {Src});
+  }
   case WebAssembly::BI__builtin_wasm_trunc_saturate_s_i32_f32:
   case WebAssembly::BI__builtin_wasm_trunc_saturate_s_i32_f64:
   case WebAssembly::BI__builtin_wasm_trunc_saturate_s_i64_f32:
diff --git a/test/CodeGen/builtins-wasm.c b/test/CodeGen/builtins-wasm.c
index 436f47c7b4..71c9e66a63 100644
--- a/test/CodeGen/builtins-wasm.c
+++ b/test/CodeGen/builtins-wasm.c
@@ -85,6 +85,54 @@ unsigned int atomic_notify(int *addr, unsigned int count) {
   // WEBASSEMBLY64: call i32 @llvm.wasm.atomic.notify(i32* %{{.*}}, i32 %{{.*}})
 }
 
+int trunc_s_i32_f32(float f) {
+  return __builtin_wasm_trunc_s_i32_f32(f);
+  // WEBASSEMBLY: call i32 @llvm.wasm.trunc.signed.i32.f32(float %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+int trunc_u_i32_f32(float f) {
+  return __builtin_wasm_trunc_u_i32_f32(f);
+  // WEBASSEMBLY: call i32 @llvm.wasm.trunc.unsigned.i32.f32(float %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+int trunc_s_i32_f64(double f) {
+  return __builtin_wasm_trunc_s_i32_f64(f);
+  // WEBASSEMBLY: call i32 @llvm.wasm.trunc.signed.i32.f64(double %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+int trunc_u_i32_f64(double f) {
+  return __builtin_wasm_trunc_u_i32_f64(f);
+  // WEBASSEMBLY: call i32 @llvm.wasm.trunc.unsigned.i32.f64(double %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+long long trunc_s_i64_f32(float f) {
+  return __builtin_wasm_trunc_s_i64_f32(f);
+  // WEBASSEMBLY: call i64 @llvm.wasm.trunc.signed.i64.f32(float %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+long long trunc_u_i64_f32(float f) {
+  return __builtin_wasm_trunc_u_i64_f32(f);
+  // WEBASSEMBLY: call i64 @llvm.wasm.trunc.unsigned.i64.f32(float %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+long long trunc_s_i64_f64(double f) {
+  return __builtin_wasm_trunc_s_i64_f64(f);
+  // WEBASSEMBLY: call i64 @llvm.wasm.trunc.signed.i64.f64(double %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+long long trunc_u_i64_f64(double f) {
+  return __builtin_wasm_trunc_u_i64_f64(f);
+  // WEBASSEMBLY: call i64 @llvm.wasm.trunc.unsigned.i64.f64(double %f)
+  // WEBASSEMBLY-NEXT: ret
+}
+
 int trunc_saturate_s_i32_f32(float f) {
   return __builtin_wasm_trunc_saturate_s_i32_f32(f);
   // WEBASSEMBLY: call i32 @llvm.wasm.trunc.saturate.signed.i32.f32(float %f)