CodeGen: Cast llvm.flt.rounds result to match __builtin_flt_rounds

[edward-jones]

Summary

llvm.flt.rounds returns an i32, but the builtin expects an integer. On targets where integers are not 32-bits clang tries to bitcast the result, causing an assertion failure.

[rjmccall]

LGTM.

[edward-jones]

Awesome, is it possible for someone to commit this on my behalf?

[edward-jones]

Ping.

[rjmccall]

Did this ever get committed?

[edward-jones]

No, this doesn't seem to have been committed yet.

[mskvortsov]

@asl The change enables to build newlib. Could you commit this?

[asl]

Committed, thanks!

lib/CodeGen/CGBuiltin.cpp

case Builtin::BI__builtin_isnormal: {
     Value *IsNormal =
       Builder.CreateFCmpUGE(Abs, ConstantFP::get(V->getContext(), Smallest),
                             "isnormal");
     V = Builder.CreateAnd(Eq, IsLessThanInf, "and");
     V = Builder.CreateAnd(V, IsNormal, "and");
     return RValue::get(Builder.CreateZExt(V, ConvertType(E->getType())));
   }
 
+  case Builtin::BI__builtin_flt_rounds: {
+    Value *F = CGM.getIntrinsic(Intrinsic::flt_rounds);
+
+    llvm::Type *ResultType = ConvertType(E->getType());
+    Value *Result = Builder.CreateCall(F);
+    if (Result->getType() != ResultType)
+      Result = Builder.CreateIntCast(Result, ResultType, /*isSigned*/true,
+                                     "cast");
+    return RValue::get(Result);
+  }
+
   case Builtin::BI__builtin_fpclassify: {
     Value *V = EmitScalarExpr(E->getArg(5));
     llvm::Type *Ty = ConvertType(E->getArg(5)->getType());
 
     // Create Result
     BasicBlock *Begin = Builder.GetInsertBlock();
     BasicBlock *End = createBasicBlock("fpclassify_end", this->CurFn);
     Builder.SetInsertPoint(End);

test/CodeGen/builtins-msp430.c

+// REQUIRES: msp430-registered-target
+// RUN: %clang_cc1 -triple msp430-unknown-unknown -emit-llvm %s -o - | FileCheck %s
+
+int test_builtin_flt_rounds() {
+  // CHECK:     [[V0:[%A-Za-z0-9.]+]] = call i32 @llvm.flt.rounds()
+  // CHECK-DAG: [[V1:[%A-Za-z0-9.]+]] = trunc i32 [[V0]] to i16
+  // CHECK-DAG: ret i16 [[V1]]
+  return __builtin_flt_rounds();
+}
+

test/CodeGen/builtins.c

void test_float_builtins(float F, double D, long double LD) {
 
   res = __builtin_isnormal(F);
   // CHECK: fcmp oeq float
   // CHECK: call float @llvm.fabs.f32(float
   // CHECK: fcmp ult float {{.*}}, 0x7FF0000000000000
   // CHECK: fcmp uge float {{.*}}, 0x3810000000000000
   // CHECK: and i1
   // CHECK: and i1
+
+  res = __builtin_flt_rounds();
+  // CHECK: call i32 @llvm.flt.rounds(
 }
 
 // CHECK-LABEL: define void @test_float_builtin_ops
 void test_float_builtin_ops(float F, double D, long double LD) {
   volatile float resf;
   volatile double resd;
   volatile long double resld;