[libc-commits] [libc] Bfloat16 `*= (Multiply assign)` operator support (PR #182882)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Zorojuro (Sukumarsawant)

<details>
<summary>Changes</summary>

This PR intends to add *= operator support for Bfloat16 and tests for it .


---
Full diff: https://github.com/llvm/llvm-project/pull/182882.diff


2 Files Affected:

- (modified) libc/src/__support/FPUtil/bfloat16.h (+5) 
- (modified) libc/test/src/__support/FPUtil/bfloat16_test.cpp (+15) 


``````````diff
diff --git a/libc/src/__support/FPUtil/bfloat16.h b/libc/src/__support/FPUtil/bfloat16.h
index 13e151208567d..7d64b441bf9b2 100644
--- a/libc/src/__support/FPUtil/bfloat16.h
+++ b/libc/src/__support/FPUtil/bfloat16.h
@@ -113,6 +113,11 @@ struct BFloat16 {
   LIBC_INLINE BFloat16 operator/(BFloat16 other) const {
     return fputil::generic::div<bfloat16>(*this, other);
   }
+
+  LIBC_INLINE BFloat16 &operator*=(const BFloat16 &other) {
+    *this = *this * other;
+    return *this;
+  }
 }; // struct BFloat16
 
 } // namespace fputil
diff --git a/libc/test/src/__support/FPUtil/bfloat16_test.cpp b/libc/test/src/__support/FPUtil/bfloat16_test.cpp
index a71d971a9ad3d..48b2dfd5c4f3b 100644
--- a/libc/test/src/__support/FPUtil/bfloat16_test.cpp
+++ b/libc/test/src/__support/FPUtil/bfloat16_test.cpp
@@ -67,3 +67,18 @@ TEST_F(LlvmLibcBfloat16ConversionTest, FromInteger) {
     EXPECT_FP_EQ_ALL_ROUNDING(mpfr_bfloat, libc_bfloat);
   }
 }
+
+TEST_F(LlvmLibcBfloat16ConversionTest, MultiplyAssign) {
+  for (uint16_t i = POS_START; i <= POS_STOP; i++) {
+    for (uint16_t j = POS_START; j <= POS_STOP; j++) {
+      BFloat16 a{i}, b{j};
+      MPFRNumber mpfr_a{a}, mpfr_b{j};
+      MPFRNumber mpfr_c = mpfr_a;
+      mpfr_c.mul(mpfr_b);
+      BFloat16 mpfr_bfloat = mpfr_c.as<BFloat16>();
+      a *= b;
+      BFloat16 libc_bfloat = a;
+      EXPECT_FP_EQ_ALL_ROUNDING(mpfr_bfloat, libc_bfloat);
+    }
+  }
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/182882