[builtins] Divide shouldn't underflow if rounded result would be normal.

We were treating certain edge cases that are actually normal as denormal
results, and flushing them to zero; we shouldn't do that. Not sure this
is the cleanest way to implement this edge case, but I wanted to avoid
adding any code on the common path.

Differential Revision: https://reviews.llvm.org/D59070

llvm-svn: 356529

1 files changed, 7 insertions, 2 deletions

diff --git a/compiler-rt/test/builtins/Unit/divtf3_test.c b/compiler-rt/test/builtins/Unit/divtf3_test.c
index a9ff43e3885..23e1b5580b8 100644
--- a/compiler-rt/test/builtins/Unit/divtf3_test.c
+++ b/compiler-rt/test/builtins/Unit/divtf3_test.c
@@ -28,8 +28,8 @@ int test__divtf3(long double a, long double b,
     int ret = compareResultLD(x, expectedHi, expectedLo);
 
     if (ret){
-        printf("error in test__divtf3(%.20Lf, %.20Lf) = %.20Lf, "
-               "expected %.20Lf\n", a, b, x,
+        printf("error in test__divtf3(%.20Le, %.20Le) = %.20Le, "
+               "expected %.20Le\n", a, b, x,
                fromRep128(expectedHi, expectedLo));
     }
     return ret;
@@ -86,6 +86,11 @@ int main()
                      UINT64_C(0x50bf2e02f0798d36),
                      UINT64_C(0x5e6fcb6b60044078)))
         return 1;
+    if (test__divtf3(6.72420628622418701252535563464350521E-4932L,
+                     2.L,
+                     UINT64_C(0x0001000000000000),
+                     UINT64_C(0)))
+        return 1;
 
 #else
     printf("skipped\n");