[llvm] [SPIR-V] Handle bfloat in getZeroFP/getOneFP (PR #202859)
Arseniy Obolenskiy via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 15 02:01:31 PDT 2026
https://github.com/aobolensk updated https://github.com/llvm/llvm-project/pull/202859
>From b4b5ad5cf8f82a835946e991fd4e56cc093b4bf6 Mon Sep 17 00:00:00 2001
From: Arseniy Obolenskiy <arseniy.obolenskiy at amd.com>
Date: Wed, 10 Jun 2026 07:44:41 +0200
Subject: [PATCH 1/3] [SPIR-V] Handle bfloat in getZeroFP/getOneFP
---
.../Target/SPIRV/SPIRVInstructionSelector.cpp | 4 +++
.../extensions/SPV_KHR_bfloat16/bfloat16.ll | 25 ++++++++++++++++++-
2 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index 79577505157fd..92aaaee699b19 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -2924,6 +2924,8 @@ 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());
@@ -2938,6 +2940,8 @@ 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..3b4659c08d5da 100644
--- a/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
+++ b/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
@@ -4,10 +4,11 @@
; CHECK-ERROR: LLVM ERROR: OpTypeFloat type with bfloat requires the following SPIR-V extension: SPV_KHR_bfloat16
+; CHECK-DAG: %[[#glsl:]] = OpExtInstImport "GLSL.std.450"
; CHECK-DAG: OpCapability BFloat16TypeKHR
; CHECK-DAG: OpExtension "SPV_KHR_bfloat16"
; CHECK: %[[#BFLOAT:]] = OpTypeFloat 16 0
-; CHECK: %[[#]] = OpTypeVector %[[#BFLOAT]] 2
+; CHECK: %[[#VEC:]] = 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"
@@ -25,3 +26,25 @@ entry:
store <2 x bfloat> %data2, ptr @G2
ret void
}
+
+; 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>)
>From fd811a62033dff9fd3419b63c038d00f7fee0246 Mon Sep 17 00:00:00 2001
From: Arseniy Obolenskiy <arseniy.obolenskiy at amd.com>
Date: Tue, 14 Jul 2026 09:15:43 +0200
Subject: [PATCH 2/3] fix tests
---
.../extensions/SPV_KHR_bfloat16/bfloat16.ll | 48 +++++++++++++++----
1 file changed, 39 insertions(+), 9 deletions(-)
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 3b4659c08d5da..5e44f83768a76 100644
--- a/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
+++ b/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
@@ -1,18 +1,23 @@
-; 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
-; CHECK-ERROR: LLVM ERROR: OpTypeFloat type with bfloat requires the following SPIR-V extension: SPV_KHR_bfloat16
+; RUN: not llc -O0 -mtriple=spirv32-unknown-unknown %t/valid.ll -o %t.spvt 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR
-; CHECK-DAG: %[[#glsl:]] = OpExtInstImport "GLSL.std.450"
-; CHECK-DAG: OpCapability BFloat16TypeKHR
-; CHECK-DAG: OpExtension "SPV_KHR_bfloat16"
-; CHECK: %[[#BFLOAT:]] = OpTypeFloat 16 0
-; CHECK: %[[#VEC:]] = OpTypeVector %[[#BFLOAT]] 2
+; 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
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: OpCapability BFloat16TypeKHR
+; CHECK-DAG: OpExtension "SPV_KHR_bfloat16"
+; CHECK-DAG: %[[#BFLOAT:]] = OpTypeFloat 16 0
+; CHECK-DAG: %[[#VEC:]] = OpTypeVector %[[#BFLOAT]] 2
+
@G1 = global bfloat 0.0
@G2 = global <2 x bfloat> zeroinitializer
@@ -27,6 +32,31 @@ entry:
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.
+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: %[[#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]]
>From 735b3716830816afceb0578a8c31a954654652c3 Mon Sep 17 00:00:00 2001
From: Arseniy Obolenskiy <gooddoog at student.su>
Date: Wed, 15 Jul 2026 09:58:55 +0200
Subject: [PATCH 3/3] Apply suggestions from code review
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Co-authored-by: Juan Manuel Martinez Caamaño <jmartinezcaamao at gmail.com>
---
.../CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll | 4 ----
1 file changed, 4 deletions(-)
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 5e44f83768a76..99c692003225d 100644
--- a/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
+++ b/llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll
@@ -10,8 +10,6 @@
; CHECK-ERROR: LLVM ERROR: OpTypeFloat type with bfloat requires the following SPIR-V extension: SPV_KHR_bfloat16
;--- valid.ll
-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: OpCapability BFloat16TypeKHR
; CHECK-DAG: OpExtension "SPV_KHR_bfloat16"
@@ -51,8 +49,6 @@ entry:
; 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.
-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: %[[#glsl:]] = OpExtInstImport "GLSL.std.450"
; CHECK-DAG: %[[#BFLOAT:]] = OpTypeFloat 16 0
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