[libclc] 3c7f70b - libclc: Replace fmod implementation with elementwise builtin (#186083)
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Thu Mar 12 03:47:43 PDT 2026
Author: Matt Arsenault
Date: 2026-03-12T11:47:39+01:00
New Revision: 3c7f70bb9cee9bbe7b098c1b56da3a79110ffcb8
URL: https://github.com/llvm/llvm-project/commit/3c7f70bb9cee9bbe7b098c1b56da3a79110ffcb8
DIFF: https://github.com/llvm/llvm-project/commit/3c7f70bb9cee9bbe7b098c1b56da3a79110ffcb8.diff
LOG: libclc: Replace fmod implementation with elementwise builtin (#186083)
This corresponds to frem, which for whatever reason is a first
class IR instruction. The backend has a heroic freestanding
implementation that should be nearly identical to what was here.
Added:
Modified:
libclc/clc/lib/generic/math/clc_fmod.cl
Removed:
################################################################################
diff --git a/libclc/clc/lib/generic/math/clc_fmod.cl b/libclc/clc/lib/generic/math/clc_fmod.cl
index 7f60b403b53e6..629c610748618 100644
--- a/libclc/clc/lib/generic/math/clc_fmod.cl
+++ b/libclc/clc/lib/generic/math/clc_fmod.cl
@@ -6,187 +6,10 @@
//
//===----------------------------------------------------------------------===//
-#include <clc/clc_convert.h>
-#include <clc/integer/clc_clz.h>
#include <clc/internal/clc.h>
-#include <clc/math/clc_floor.h>
-#include <clc/math/clc_fma.h>
-#include <clc/math/clc_ldexp.h>
-#include <clc/math/clc_trunc.h>
-#include <clc/math/math.h>
-#include <clc/shared/clc_max.h>
-_CLC_DEF _CLC_OVERLOAD float __clc_fmod(float x, float y) {
- int ux = __clc_as_int(x);
- int ax = ux & EXSIGNBIT_SP32;
- float xa = __clc_as_float(ax);
- int sx = ux ^ ax;
- int ex = ax >> EXPSHIFTBITS_SP32;
-
- int uy = __clc_as_int(y);
- int ay = uy & EXSIGNBIT_SP32;
- float ya = __clc_as_float(ay);
- int ey = ay >> EXPSHIFTBITS_SP32;
-
- float xr = __clc_as_float(0x3f800000 | (ax & 0x007fffff));
- float yr = __clc_as_float(0x3f800000 | (ay & 0x007fffff));
- int c;
- int k = ex - ey;
-
- while (k > 0) {
- c = xr >= yr;
- xr -= c ? yr : 0.0f;
- xr += xr;
- --k;
- }
-
- c = xr >= yr;
- xr -= c ? yr : 0.0f;
-
- int lt = ex < ey;
-
- xr = lt ? xa : xr;
- yr = lt ? ya : yr;
-
- float s = __clc_as_float(ey << EXPSHIFTBITS_SP32);
- xr *= lt ? 1.0f : s;
-
- c = ax == ay;
- xr = c ? 0.0f : xr;
-
- xr = __clc_as_float(sx ^ __clc_as_int(xr));
-
- c = ax > PINFBITPATT_SP32 | ay > PINFBITPATT_SP32 | ax == PINFBITPATT_SP32 |
- ay == 0;
- xr = c ? __clc_as_float(QNANBITPATT_SP32) : xr;
-
- return xr;
-}
-
-#define __CLC_FLOAT_ONLY
#define __CLC_FUNCTION __clc_fmod
-#define __CLC_BODY <clc/shared/binary_def_scalarize.inc>
-#include <clc/math/gentype.inc>
-#undef __CLC_FUNCTION
-
-#ifdef cl_khr_fp64
-
-#pragma OPENCL EXTENSION cl_khr_fp64 : enable
-
-_CLC_DEF _CLC_OVERLOAD double __clc_fmod(double x, double y) {
- ulong ux = __clc_as_ulong(x);
- ulong ax = ux & ~SIGNBIT_DP64;
- ulong xsgn = ux ^ ax;
- double dx = __clc_as_double(ax);
- int xexp = __clc_convert_int(ax >> EXPSHIFTBITS_DP64);
- int xexp1 = 11 - (int)__clc_clz(ax & MANTBITS_DP64);
- xexp1 = xexp < 1 ? xexp1 : xexp;
-
- ulong uy = __clc_as_ulong(y);
- ulong ay = uy & ~SIGNBIT_DP64;
- double dy = __clc_as_double(ay);
- int yexp = __clc_convert_int(ay >> EXPSHIFTBITS_DP64);
- int yexp1 = 11 - (int)__clc_clz(ay & MANTBITS_DP64);
- yexp1 = yexp < 1 ? yexp1 : yexp;
-
- // First assume |x| > |y|
-
- // Set ntimes to the number of times we need to do a
- // partial remainder. If the exponent of x is an exact multiple
- // of 53 larger than the exponent of y, and the mantissa of x is
- // less than the mantissa of y, ntimes will be one too large
- // but it doesn't matter - it just means that we'll go round
- // the loop below one extra time.
- int ntimes = __clc_max(0, (xexp1 - yexp1) / 53);
- double w = __clc_ldexp(dy, ntimes * 53);
- w = ntimes == 0 ? dy : w;
- double scale = ntimes == 0 ? 1.0 : 0x1.0p-53;
-
- // Each time round the loop we compute a partial remainder.
- // This is done by subtracting a large multiple of w
- // from x each time, where w is a scaled up version of y.
- // The subtraction must be performed exactly in quad
- // precision, though the result at each stage can
- // fit exactly in a double precision number.
- int i;
- double t, v, p, pp;
-
- for (i = 0; i < ntimes; i++) {
- // Compute integral multiplier
- t = __clc_trunc(dx / w);
-
- // Compute w * t in quad precision
- p = w * t;
- pp = __clc_fma(w, t, -p);
+#define __CLC_IMPL_FUNCTION(x) __builtin_elementwise_fmod
+#define __CLC_BODY <clc/shared/binary_def.inc>
- // Subtract w * t from dx
- v = dx - p;
- dx = v + (((dx - v) - p) - pp);
-
- // If t was one too large, dx will be negative. Add back one w.
- dx += dx < 0.0 ? w : 0.0;
-
- // Scale w down by 2^(-53) for the next iteration
- w *= scale;
- }
-
- // One more time
- t = __clc_floor(dx / w);
-
- p = w * t;
- pp = __clc_fma(w, t, -p);
- v = dx - p;
- dx = v + (((dx - v) - p) - pp);
- i = dx < 0.0;
- dx += i ? w : 0.0;
-
- // At this point, dx lies in the range [0,dy)
- double ret = __clc_as_double(xsgn ^ __clc_as_ulong(dx));
- dx = __clc_as_double(ax);
-
- // Now handle |x| == |y|
- int c = dx == dy;
- t = __clc_as_double(xsgn);
- ret = c ? t : ret;
-
- // Next, handle |x| < |y|
- c = dx < dy;
- ret = c ? x : ret;
-
- // We don't need anything special for |x| == 0
-
- // |y| is 0
- c = dy == 0.0;
- ret = c ? __clc_as_double(QNANBITPATT_DP64) : ret;
-
- // y is +-Inf, NaN
- c = yexp > BIASEDEMAX_DP64;
- t = y == y ? x : y;
- ret = c ? t : ret;
-
- // x is +=Inf, NaN
- c = xexp > BIASEDEMAX_DP64;
- ret = c ? __clc_as_double(QNANBITPATT_DP64) : ret;
-
- return ret;
-}
-
-#define __CLC_DOUBLE_ONLY
-#define __CLC_FUNCTION __clc_fmod
-#define __CLC_BODY <clc/shared/binary_def_scalarize.inc>
-#include <clc/math/gentype.inc>
-#undef __CLC_FUNCTION
-
-#endif
-
-#ifdef cl_khr_fp16
-
-#pragma OPENCL EXTENSION cl_khr_fp16 : enable
-
-// Forward the half version of this builtin onto the float one
-#define __CLC_HALF_ONLY
-#define __CLC_FUNCTION __clc_fmod
-#define __CLC_BODY <clc/math/binary_def_via_fp32.inc>
#include <clc/math/gentype.inc>
-
-#endif
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