Support f*_fast

Author: cijiugechu

src/builder.rs

@@ -971,24 +971,44 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
 
     fn fadd_fast(&mut self, lhs: RValue<'gcc>, rhs: RValue<'gcc>) -> RValue<'gcc> {
         // NOTE: it seems like we cannot enable fast-mode for a single operation in GCC.
+        if let Some(value) =
+            self.f16_arithmetic_binary_op(lhs, rhs, |this, lhs, rhs| this.assign_to_var(lhs + rhs))
+        {
+            return value;
+        }
         let result = set_rvalue_location(self, lhs + rhs);
         self.assign_to_var(result)
     }
 
     fn fsub_fast(&mut self, lhs: RValue<'gcc>, rhs: RValue<'gcc>) -> RValue<'gcc> {
         // NOTE: it seems like we cannot enable fast-mode for a single operation in GCC.
+        if let Some(value) =
+            self.f16_arithmetic_binary_op(lhs, rhs, |this, lhs, rhs| this.assign_to_var(lhs - rhs))
+        {
+            return value;
+        }
         let result = set_rvalue_location(self, lhs - rhs);
         self.assign_to_var(result)
     }
 
     fn fmul_fast(&mut self, lhs: RValue<'gcc>, rhs: RValue<'gcc>) -> RValue<'gcc> {
         // NOTE: it seems like we cannot enable fast-mode for a single operation in GCC.
+        if let Some(value) =
+            self.f16_arithmetic_binary_op(lhs, rhs, |this, lhs, rhs| this.assign_to_var(lhs * rhs))
+        {
+            return value;
+        }
         let result = set_rvalue_location(self, lhs * rhs);
         self.assign_to_var(result)
     }
 
     fn fdiv_fast(&mut self, lhs: RValue<'gcc>, rhs: RValue<'gcc>) -> RValue<'gcc> {
         // NOTE: it seems like we cannot enable fast-mode for a single operation in GCC.
+        if let Some(value) =
+            self.f16_arithmetic_binary_op(lhs, rhs, |this, lhs, rhs| this.assign_to_var(lhs / rhs))
+        {
+            return value;
+        }
         let result = set_rvalue_location(self, lhs / rhs);
         self.assign_to_var(result)
     }

tests/run/f16.rs

@@ -8,7 +8,7 @@
 
 use std::cmp::Ordering;
 use std::hint::black_box;
-use std::intrinsics::{fmaf16, powif16};
+use std::intrinsics::{fadd_fast, fdiv_fast, fmaf16, fmul_fast, fsub_fast, powif16};
 
 unsafe extern "C" {
     #[link_name = "llvm.fma.f16"]
@@ -45,6 +45,10 @@ fn main() {
     assert_f16_bits(two * three, 0x4600);
     assert_f16_bits(two / one, 0x4000);
     assert_f16_bits(-three, 0xc200);
+    assert_f16_bits(unsafe { fadd_fast(one, two) }, 0x4200);
+    assert_f16_bits(unsafe { fsub_fast(two, one) }, 0x3c00);
+    assert_f16_bits(unsafe { fmul_fast(two, three) }, 0x4600);
+    assert_f16_bits(unsafe { fdiv_fast(three, two) }, 0x3e00);
     assert_f16_bits(fmaf16(one, two, -three), 0xbc00);
     assert_f16_bits(unsafe { llvm_fma_f16(one, two, -three) }, 0xbc00);
     assert_f16_bits(powif16(two, 3), 0x4800);