Add an implementation for f128 multiplication

Author: tgross35

README.md

@@ -249,7 +249,7 @@ These builtins are needed to support `f16` and `f128`, which are in the process
 - [ ] floatsitf.c
 - [ ] floatunditf.c
 - [ ] floatunsitf.c
-- [ ] multf3.c
+- [x] multf3.c
 - [ ] powitf2.c
 - [ ] ppc/fixtfdi.c
 - [ ] ppc/fixunstfdi.c

build.rs

@@ -479,7 +479,6 @@ mod c {
                 ("__floatsitf", "floatsitf.c"),
                 ("__floatunditf", "floatunditf.c"),
                 ("__floatunsitf", "floatunsitf.c"),
-                ("__multf3", "multf3.c"),
                 ("__divtf3", "divtf3.c"),
                 ("__powitf2", "powitf2.c"),
                 ("__fe_getround", "fp_mode.c"),
@@ -504,7 +503,6 @@ mod c {
                 ("__fixunstfsi", "fixunstfsi.c"),
                 ("__floatunsitf", "floatunsitf.c"),
                 ("__fe_getround", "fp_mode.c"),
-                ("__divtf3", "divtf3.c"),
             ]);
         }
 
@@ -517,7 +515,6 @@ mod c {
                 ("__fixunstfsi", "fixunstfsi.c"),
                 ("__floatunsitf", "floatunsitf.c"),
                 ("__fe_getround", "fp_mode.c"),
-                ("__divtf3", "divtf3.c"),
             ]);
         }
 

src/float/mul.rs

@@ -199,6 +199,11 @@ intrinsics! {
         mul(a, b)
     }
 
+    #[cfg(not(feature = "no-f16-f128"))]
+    pub extern "C" fn __multf3(a: f128, b: f128) -> f128 {
+        mul(a, b)
+    }
+
     #[cfg(target_arch = "arm")]
     pub extern "C" fn __mulsf3vfp(a: f32, b: f32) -> f32 {
         a * b

testcrate/tests/mul.rs

@@ -1,4 +1,6 @@
 #![allow(unused_macros)]
+#![feature(f128)]
+#![feature(f16)]
 
 use core::ops::Mul;
 use testcrate::*;
@@ -114,6 +116,18 @@ fn float_mul() {
         f32, __mulsf3, Single, all();
         f64, __muldf3, Double, all();
     );
+
+    #[cfg(not(feature = "no-f16-f128"))]
+    {
+        use compiler_builtins::float::mul::__multf3;
+
+        float_mul!(
+            f128, __multf3, Quad,
+            // FIXME(llvm): there is a bug in LLVM rt.
+            // See <https://github.com/llvm/llvm-project/issues/91840>.
+            not(any(feature = "no-sys-f128", all(target_arch = "aarch64", target_os = "linux")));
+        );
+    }
 }
 
 #[cfg(target_arch = "arm")]