[libclc] libclc: Use select function instead of ?: for some fp selects (PR #187253)

[Matt Arsenault via cfe-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/187253

It seems that ?: is not quite equivalent to select for floating-point
vectors. With ?:, the resulting IR involves integer bitcasts and
integer vector typed select. Use select so this is an fp-select. This
enables finite math only contexts to optimize out the select.

This feels like it's a clang bug though.

>From ee53973770851aa761b5c6fcdcd701730c9895ee Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Tue, 17 Mar 2026 15:59:38 +0100
Subject: [PATCH] libclc: Use select function instead of ?: for some fp selects

It seems that ?: is not quite equivalent to select for floating-point
vectors. With ?:, the resulting IR involves integer bitcasts and
integer vector typed select. Use select so this is an fp-select. This
enables finite math only contexts to optimize out the select.

This feels like it's a clang bug though.
---
 libclc/clc/lib/generic/math/clc_cos.inc | 6 +++---
 libclc/clc/lib/generic/math/clc_sin.inc | 5 +++--
 libclc/clc/lib/generic/math/clc_tan.inc | 5 +++--
 3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/libclc/clc/lib/generic/math/clc_cos.inc b/libclc/clc/lib/generic/math/clc_cos.inc
index 34cbbc69614a5..d004ef2c95f6d 100644
--- a/libclc/clc/lib/generic/math/clc_cos.inc
+++ b/libclc/clc/lib/generic/math/clc_cos.inc
@@ -9,8 +9,7 @@
 #if __CLC_FPSIZE == 32
 
 _CLC_OVERLOAD _CLC_DEF __CLC_FLOATN __clc_cos(__CLC_FLOATN x) {
-  x = __clc_isinf(x) ? __CLC_GENTYPE_NAN : x;
-
+  x = __clc_select(x, __CLC_GENTYPE_NAN, __clc_isinf(x));
   __CLC_FLOATN absx = __clc_fabs(x);
 
   __CLC_FLOATN r0, r1;
@@ -32,7 +31,8 @@ _CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_cos(__CLC_GENTYPE x) {
 #elif __CLC_FPSIZE == 64
 
 _CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_cos(__CLC_GENTYPE x) {
-  x = __clc_isinf(x) ? __CLC_GENTYPE_NAN : x;
+  x = __clc_select(x, __CLC_GENTYPE_NAN,
+                   __CLC_CONVERT_S_GENTYPE(__clc_isinf(x)));
 
   __CLC_GENTYPE absx = __clc_fabs(x);
 
diff --git a/libclc/clc/lib/generic/math/clc_sin.inc b/libclc/clc/lib/generic/math/clc_sin.inc
index 973833ba0c2fc..caf9c6372aaad 100644
--- a/libclc/clc/lib/generic/math/clc_sin.inc
+++ b/libclc/clc/lib/generic/math/clc_sin.inc
@@ -9,7 +9,7 @@
 #if __CLC_FPSIZE == 32
 
 _CLC_OVERLOAD _CLC_DEF __CLC_FLOATN __clc_sin(__CLC_FLOATN x) {
-  x = __clc_isinf(x) ? __CLC_GENTYPE_NAN : x;
+  x = __clc_select(x, __CLC_GENTYPE_NAN, __clc_isinf(x));
 
   __CLC_FLOATN absx = __clc_fabs(x);
 
@@ -33,7 +33,8 @@ _CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_sin(__CLC_GENTYPE x) {
 #elif __CLC_FPSIZE == 64
 
 _CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_sin(__CLC_GENTYPE x) {
-  x = __clc_isinf(x) ? __CLC_GENTYPE_NAN : x;
+  x = __clc_select(x, __CLC_GENTYPE_NAN,
+                   __CLC_CONVERT_S_GENTYPE(__clc_isinf(x)));
 
   __CLC_GENTYPE absx = __clc_fabs(x);
 
diff --git a/libclc/clc/lib/generic/math/clc_tan.inc b/libclc/clc/lib/generic/math/clc_tan.inc
index f1c3c0de11bc3..07acee0219e10 100644
--- a/libclc/clc/lib/generic/math/clc_tan.inc
+++ b/libclc/clc/lib/generic/math/clc_tan.inc
@@ -9,7 +9,7 @@
 #if __CLC_FPSIZE == 32
 
 _CLC_DEF _CLC_OVERLOAD __CLC_GENTYPE __clc_tan(__CLC_GENTYPE x) {
-  x = __clc_isinf(x) ? __CLC_GENTYPE_NAN : x;
+  x = __clc_select(x, __CLC_GENTYPE_NAN, __clc_isinf(x));
 
   __CLC_GENTYPE absx = __clc_fabs(x);
   __CLC_UINTN x_signbit = __CLC_AS_UINTN(x) & SIGNBIT_SP32;
@@ -24,7 +24,8 @@ _CLC_DEF _CLC_OVERLOAD __CLC_GENTYPE __clc_tan(__CLC_GENTYPE x) {
 #elif __CLC_FPSIZE == 64
 
 _CLC_DEF _CLC_OVERLOAD __CLC_GENTYPE __clc_tan(__CLC_GENTYPE x) {
-  x = __clc_isinf(x) ? __CLC_GENTYPE_NAN : x;
+  x = __clc_select(x, __CLC_GENTYPE_NAN,
+                   __CLC_CONVERT_S_GENTYPE(__clc_isinf(x)));
 
   __CLC_GENTYPE y = __clc_fabs(x);