commit 47408353a355c7e2db7b277b05f928ffd65e2827
author Jan Vesely <jan.vesely@rutgers.edu> Tue May 15 04:22:43 2018 +0000
committer Copybara-Service <copybara-worker@google.com> Sun Aug 30 16:12:39 2020 -0700
tree dbb5a2a53347d8860857d7b0f3c324dca33478cb
parent 3a22f21878cd34ef9e7bc5a540a63e7fd24458c0

rootn: Use denormal path only

It's OK to either flush to 0 or return denormal result if the device
does not support denormals. See sec 7.2 and 7.5.3 of OCL specs
Use 0.0f explicitly intead of relying on GPU to flush it.
Fixes CTS on carrizo and turks

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Acked-by: Aaron Watry <awatry@gmail.com>
Tested-by: Aaron Watry <awatry@gmail.com>
llvm-svn: 332324
GitOrigin-RevId: 58fdb3b09aae005c594ea66bfb85b395d7193636

generic/lib/math/clc_rootn.cl

diff --git a/generic/lib/math/clc_rootn.cl b/generic/lib/math/clc_rootn.cl
index d7ee185..0a2c98d 100644
--- a/generic/lib/math/clc_rootn.cl
+++ b/generic/lib/math/clc_rootn.cl
@@ -170,16 +170,7 @@
     tv = USE_TABLE(exp_tbl_ep, j);
 
     float expylogx = mad(tv.s0, poly, mad(tv.s1, poly, tv.s1)) + tv.s0;
-    float sexpylogx;
-    if (!__clc_fp32_subnormals_supported()) {
-		int explg = ((as_uint(expylogx) & EXPBITS_SP32 >> 23) - 127);
-		m = (23-(m + 149)) == 0 ? 1: m;
-		uint mantissa =  ((as_uint(expylogx) & MANTBITS_SP32)|IMPBIT_SP32) >> (23-(m + 149));
-		sexpylogx = as_float(mantissa);
-    } else {
-		sexpylogx = expylogx * as_float(0x1 << (m + 149));
-    }
-
+    float sexpylogx = __clc_fp32_subnormals_supported() ? expylogx * as_float(0x1 << (m + 149)) : 0.0f;
 
     float texpylogx = as_float(as_int(expylogx) + m2);
     expylogx = m < -125 ? sexpylogx : texpylogx;