[llvm] 2730fc8 - [SPIR-V] Handle bfloat in getZeroFP/getOneFP (#202859)

[via llvm-commits]

Author: Arseniy Obolenskiy
Date: 2026-07-18T10:36:10+02:00
New Revision: 2730fc8a1a46ea92bbe91e3fc31897498617e076

URL: https://github.com/llvm/llvm-project/commit/2730fc8a1a46ea92bbe91e3fc31897498617e076
DIFF: https://github.com/llvm/llvm-project/commit/2730fc8a1a46ea92bbe91e3fc31897498617e076.diff

LOG: [SPIR-V] Handle bfloat in getZeroFP/getOneFP (#202859)

Related spirv-val change:
https://github.com/KhronosGroup/SPIRV-Tools/pull/6734

---------

Co-authored-by: Juan Manuel Martinez Caamaño <jmartinezcaamao at gmail.com>

Added: 
    

Modified: 
    llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
    llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index deaf6add76ed9..d8289dc786f45 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -3072,6 +3072,8 @@ static APFloat getZeroFP(const Type *LLVMFloatTy) {
   switch (LLVMFloatTy->getScalarType()->getTypeID()) {
   case Type::HalfTyID:
     return APFloat::getZero(APFloat::IEEEhalf());
+  case Type::BFloatTyID:
+    return APFloat::getZero(APFloat::BFloat());
   default:
   case Type::FloatTyID:
     return APFloat::getZero(APFloat::IEEEsingle());
@@ -3086,6 +3088,8 @@ static APFloat getOneFP(const Type *LLVMFloatTy) {
   switch (LLVMFloatTy->getScalarType()->getTypeID()) {
   case Type::HalfTyID:
     return APFloat::getOne(APFloat::IEEEhalf());
+  case Type::BFloatTyID:
+    return APFloat::getOne(APFloat::BFloat());
   default:
   case Type::FloatTyID:
     return APFloat::getOne(APFloat::IEEEsingle());

diff  --git a/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll b/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
index 92652f1faefc0..99c692003225d 100644
--- a/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
+++ b/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
@@ -1,16 +1,20 @@
-; RUN: not llc -O0 -mtriple=spirv32-unknown-unknown %s -o %t.spvt 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR
-; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown --spirv-ext=+SPV_KHR_bfloat16 %s -o - | FileCheck %s
-; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown --spirv-ext=+SPV_KHR_bfloat16 %s -o - -filetype=obj | spirv-val %}
+; RUN: split-file %s %t
+
+; RUN: not llc -O0 -mtriple=spirv32-unknown-unknown %t/valid.ll -o %t.spvt 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR
+
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown --spirv-ext=+SPV_KHR_bfloat16 %t/valid.ll -o - | FileCheck %t/valid.ll
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown --spirv-ext=+SPV_KHR_bfloat16 %t/valid.ll -o - -filetype=obj | spirv-val %}
+
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown --spirv-ext=+SPV_KHR_bfloat16 %t/saturate.ll -o - | FileCheck %t/saturate.ll
 
 ; CHECK-ERROR: LLVM ERROR: OpTypeFloat type with bfloat requires the following SPIR-V extension: SPV_KHR_bfloat16
 
+;--- valid.ll
+
 ; CHECK-DAG: OpCapability BFloat16TypeKHR
 ; CHECK-DAG: OpExtension "SPV_KHR_bfloat16"
-; CHECK: %[[#BFLOAT:]] = OpTypeFloat 16 0
-; CHECK: %[[#]] = OpTypeVector %[[#BFLOAT]] 2
-
-target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64"
-target triple = "spir64-unknown-unknown"
+; CHECK-DAG: %[[#BFLOAT:]] = OpTypeFloat 16 0
+; CHECK-DAG: %[[#VEC:]] = OpTypeVector %[[#BFLOAT]] 2
 
 @G1 = global bfloat 0.0
 @G2 = global <2 x bfloat> zeroinitializer
@@ -25,3 +29,48 @@ entry:
   store <2 x bfloat> %data2, ptr @G2
   ret void
 }
+
+; CHECK-DAG: %[[#]] = OpConstantNull %[[#BFLOAT]]
+; CHECK-DAG: %[[#one:]] = OpConstant %[[#BFLOAT]] 16256
+; CHECK-DAG: %[[#]] = OpConstantNull %[[#VEC]]
+; CHECK-DAG: %[[#]] = OpConstantComposite %[[#VEC]] %[[#one]] %[[#one]]
+
+define spir_func bfloat @one_bfloat() {
+entry:
+  ret bfloat 1.0
+}
+
+define spir_func <2 x bfloat> @one_bfloat2() {
+entry:
+  ret <2 x bfloat> <bfloat 1.0, bfloat 1.0>
+}
+
+;--- saturate.ll
+; GLSL.std.450 defines its floating-point operands as IEEE 754 encoded
+; OpTypeFloat, so FClamp on bfloat is not currently representable in a
+; spirv-val-valid module. Check the lowering with FileCheck only.
+
+; CHECK-DAG: %[[#glsl:]] = OpExtInstImport "GLSL.std.450"
+; CHECK-DAG: %[[#BFLOAT:]] = OpTypeFloat 16 0
+; CHECK-DAG: %[[#VEC:]] = OpTypeVector %[[#BFLOAT]] 2
+; CHECK-DAG: %[[#zero:]] = OpConstantNull %[[#BFLOAT]]
+; CHECK-DAG: %[[#one:]] = OpConstant %[[#BFLOAT]] 16256
+; CHECK-DAG: %[[#vec_zero:]] = OpConstantNull %[[#VEC]]
+; CHECK-DAG: %[[#vec_one:]] = OpConstantComposite %[[#VEC]] %[[#one]] %[[#one]]
+
+define spir_func bfloat @saturate_bfloat(bfloat %a) {
+entry:
+  ; CHECK: %[[#]] = OpExtInst %[[#BFLOAT]] %[[#glsl]] FClamp %[[#]] %[[#zero]] %[[#one]]
+  %r = call bfloat @llvm.spv.saturate.bf16(bfloat %a)
+  ret bfloat %r
+}
+
+define spir_func <2 x bfloat> @saturate_bfloat2(<2 x bfloat> %a) {
+entry:
+  ; CHECK: %[[#]] = OpExtInst %[[#VEC]] %[[#glsl]] FClamp %[[#]] %[[#vec_zero]] %[[#vec_one]]
+  %r = call <2 x bfloat> @llvm.spv.saturate.v2bf16(<2 x bfloat> %a)
+  ret <2 x bfloat> %r
+}
+
+declare bfloat @llvm.spv.saturate.bf16(bfloat)
+declare <2 x bfloat> @llvm.spv.saturate.v2bf16(<2 x bfloat>)