Merge pull request #18920 from r-devulap/exp-underflow

BUG: Report underflow condition in AVX implementation of np.exp

2 files changed, 18 insertions, 0 deletions

diff --git a/numpy/core/src/umath/loops_exponent_log.dispatch.c.src b/numpy/core/src/umath/loops_exponent_log.dispatch.c.src
index 1dc24b226..291ce4518 100644
--- a/numpy/core/src/umath/loops_exponent_log.dispatch.c.src
+++ b/numpy/core/src/umath/loops_exponent_log.dispatch.c.src
@@ -465,6 +465,7 @@ simd_exp_FLOAT(npy_float * op,
 
     @mask@ xmax_mask, xmin_mask, nan_mask, inf_mask;
     @mask@ overflow_mask = @isa@_get_partial_load_mask_ps(0, num_lanes);
+    @mask@ underflow_mask = @isa@_get_partial_load_mask_ps(0, num_lanes);
     @mask@ load_mask = @isa@_get_full_load_mask_ps();
     npy_intp num_remaining_elements = array_size;
 
@@ -491,6 +492,7 @@ simd_exp_FLOAT(npy_float * op,
         inf_mask = _mm@vsize@_cmp_ps@vsub@(x, inf, _CMP_EQ_OQ);
         overflow_mask = @or_masks@(overflow_mask,
                                     @xor_masks@(xmax_mask, inf_mask));
+        underflow_mask = @or_masks@(underflow_mask, xmin_mask);
 
         x = @isa@_set_masked_lanes_ps(x, zeros_f, @or_masks@(
                                     @or_masks@(nan_mask, xmin_mask), xmax_mask));
@@ -539,6 +541,10 @@ simd_exp_FLOAT(npy_float * op,
     if (@mask_to_int@(overflow_mask)) {
         npy_set_floatstatus_overflow();
     }
+
+    if (@mask_to_int@(underflow_mask)) {
+        npy_set_floatstatus_underflow();
+    }
 }
 
 /*
@@ -740,6 +746,7 @@ AVX512F_exp_DOUBLE(npy_double * op,
     __m512d mTable_tail_3 = _mm512_loadu_pd(&(EXP_Table_tail[8*3]));
 
     __mmask8 overflow_mask = avx512_get_partial_load_mask_pd(0, num_lanes);
+    __mmask8 underflow_mask = avx512_get_partial_load_mask_pd(0, num_lanes);
     __mmask8 load_mask = avx512_get_full_load_mask_pd();
     __mmask8 xmin_mask, xmax_mask, inf_mask, nan_mask, nearzero_mask;
 
@@ -769,6 +776,7 @@ AVX512F_exp_DOUBLE(npy_double * op,
         nearzero_mask = _mm512_kxor(nearzero_mask, nan_mask);
         overflow_mask = _mm512_kor(overflow_mask,
                                 _mm512_kxor(xmax_mask, inf_mask));
+        underflow_mask = _mm512_kor(underflow_mask, xmax_mask);
         x = avx512_set_masked_lanes_pd(x, zeros_d,
                         _mm512_kor(_mm512_kor(nan_mask, xmin_mask),
                             _mm512_kor(xmax_mask, nearzero_mask)));
@@ -828,6 +836,10 @@ AVX512F_exp_DOUBLE(npy_double * op,
     if (overflow_mask) {
         npy_set_floatstatus_overflow();
     }
+
+    if (underflow_mask) {
+        npy_set_floatstatus_underflow();
+    }
 }
 /*
  * Vectorized implementation of log double using AVX512
diff --git a/numpy/core/tests/test_umath.py b/numpy/core/tests/test_umath.py
index 75e1c99d3..572e736a0 100644
--- a/numpy/core/tests/test_umath.py
+++ b/numpy/core/tests/test_umath.py
@@ -919,6 +919,12 @@ class TestSpecialFloats:
             assert_raises(FloatingPointError, np.exp, np.float64(800.))
             assert_raises(FloatingPointError, np.exp, np.float64(1E19))
 
+        with np.errstate(under='raise'):
+            assert_raises(FloatingPointError, np.exp, np.float32(-1000.))
+            assert_raises(FloatingPointError, np.exp, np.float32(-1E19))
+            assert_raises(FloatingPointError, np.exp, np.float64(-1000.))
+            assert_raises(FloatingPointError, np.exp, np.float64(-1E19))
+
     def test_log_values(self):
         with np.errstate(all='ignore'):
             x = [np.nan,  np.nan, np.inf, np.nan, -np.inf, np.nan]