[llvm] [LLVM][IR] Add textual shorthand for specifying constant vector splats. (PR #74620)
Paul Walker via llvm-commits
llvm-commits at lists.llvm.org
Fri Dec 8 06:22:58 PST 2023
https://github.com/paulwalker-arm updated https://github.com/llvm/llvm-project/pull/74620
>From 4e175dc0648deae0a32b31987b04aa6380c455e7 Mon Sep 17 00:00:00 2001
From: Paul Walker <paul.walker at arm.com>
Date: Wed, 29 Nov 2023 13:54:33 +0000
Subject: [PATCH] [LLVM][IR] Add textual shorthand for specifying constant
vector splats.
Add LL parsing for `<N x ty> splat(ty <imm>)` that lowers onto
ConstantInt::get() for integer types and ConstantFP::get() for
floating-point types.
The intent is to extend ConstantInt/FP classes to support vector
types rather than redirecting to other constant classes as the
get() methods do today.
This patch gives IR writers the convenience of using the shorthand
today, thus allowing existing tests to be ported.
---
llvm/docs/LangRef.rst | 5 ++
llvm/include/llvm/AsmParser/LLParser.h | 1 +
llvm/include/llvm/AsmParser/LLToken.h | 1 +
llvm/lib/AsmParser/LLLexer.cpp | 1 +
llvm/lib/AsmParser/LLParser.cpp | 27 ++++++++
.../Assembler/constant-splat-diagnostics.ll | 40 +++++++++++
llvm/test/Assembler/constant-splat.ll | 67 +++++++++++++++++++
7 files changed, 142 insertions(+)
create mode 100644 llvm/test/Assembler/constant-splat-diagnostics.ll
create mode 100644 llvm/test/Assembler/constant-splat.ll
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index f5e8065ca1dc6..adda52b33c789 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -4299,6 +4299,11 @@ constants and smaller complex constants.
"``< i32 42, i32 11, i32 74, i32 100 >``". Vector constants
must have :ref:`vector type <t_vector>`, and the number and types of
elements must match those specified by the type.
+
+ When creating a vector whose elements have the same constant value, the
+ preferred syntax is ``splat (<Ty> Val)``. For example: "``splat (i32 11)``".
+ These vector constants must have ::ref:`vector type <t_vector>` with an
+ element type that matches the ``splat`` operand.
**Zero initialization**
The string '``zeroinitializer``' can be used to zero initialize a
value to zero of *any* type, including scalar and
diff --git a/llvm/include/llvm/AsmParser/LLParser.h b/llvm/include/llvm/AsmParser/LLParser.h
index a1f330acb1c23..54bc3e582e01a 100644
--- a/llvm/include/llvm/AsmParser/LLParser.h
+++ b/llvm/include/llvm/AsmParser/LLParser.h
@@ -64,6 +64,7 @@ namespace llvm {
t_Poison, // No value.
t_EmptyArray, // No value: []
t_Constant, // Value in ConstantVal.
+ t_ConstantSplat, // Value in ConstantVal.
t_InlineAsm, // Value in FTy/StrVal/StrVal2/UIntVal.
t_ConstantStruct, // Value in ConstantStructElts.
t_PackedConstantStruct // Value in ConstantStructElts.
diff --git a/llvm/include/llvm/AsmParser/LLToken.h b/llvm/include/llvm/AsmParser/LLToken.h
index 0aa0093e8efbd..147cf56c821aa 100644
--- a/llvm/include/llvm/AsmParser/LLToken.h
+++ b/llvm/include/llvm/AsmParser/LLToken.h
@@ -336,6 +336,7 @@ enum Kind {
kw_extractelement,
kw_insertelement,
kw_shufflevector,
+ kw_splat,
kw_extractvalue,
kw_insertvalue,
kw_blockaddress,
diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index bf01b39e6f971..919c69fe2783e 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -698,6 +698,7 @@ lltok::Kind LLLexer::LexIdentifier() {
KEYWORD(uinc_wrap);
KEYWORD(udec_wrap);
+ KEYWORD(splat);
KEYWORD(vscale);
KEYWORD(x);
KEYWORD(blockaddress);
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 1afde5d640403..fb9e1ba875e1f 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -3981,6 +3981,21 @@ bool LLParser::parseValID(ValID &ID, PerFunctionState *PFS, Type *ExpectedTy) {
return false;
}
+ case lltok::kw_splat: {
+ Lex.Lex();
+ if (parseToken(lltok::lparen, "expected '(' after vector splat"))
+ return true;
+ Constant *C;
+ if (parseGlobalTypeAndValue(C))
+ return true;
+ if (parseToken(lltok::rparen, "expected ')' at end of vector splat"))
+ return true;
+
+ ID.ConstantVal = C;
+ ID.Kind = ValID::t_ConstantSplat;
+ return false;
+ }
+
case lltok::kw_getelementptr:
case lltok::kw_shufflevector:
case lltok::kw_insertelement:
@@ -5824,6 +5839,17 @@ bool LLParser::convertValIDToValue(Type *Ty, ValID &ID, Value *&V,
"' but expected '" + getTypeString(Ty) + "'");
V = ID.ConstantVal;
return false;
+ case ValID::t_ConstantSplat:
+ if (!Ty->isVectorTy())
+ return error(ID.Loc, "vector constant must have vector type");
+ if (ID.ConstantVal->getType() != Ty->getScalarType())
+ return error(ID.Loc, "constant expression type mismatch: got type '" +
+ getTypeString(ID.ConstantVal->getType()) +
+ "' but expected '" +
+ getTypeString(Ty->getScalarType()) + "'");
+ V = ConstantVector::getSplat(cast<VectorType>(Ty)->getElementCount(),
+ ID.ConstantVal);
+ return false;
case ValID::t_ConstantStruct:
case ValID::t_PackedConstantStruct:
if (StructType *ST = dyn_cast<StructType>(Ty)) {
@@ -5861,6 +5887,7 @@ bool LLParser::parseConstantValue(Type *Ty, Constant *&C) {
case ValID::t_APFloat:
case ValID::t_Undef:
case ValID::t_Constant:
+ case ValID::t_ConstantSplat:
case ValID::t_ConstantStruct:
case ValID::t_PackedConstantStruct: {
Value *V;
diff --git a/llvm/test/Assembler/constant-splat-diagnostics.ll b/llvm/test/Assembler/constant-splat-diagnostics.ll
new file mode 100644
index 0000000000000..464250d03ea28
--- /dev/null
+++ b/llvm/test/Assembler/constant-splat-diagnostics.ll
@@ -0,0 +1,40 @@
+; RUN: rm -rf %t && split-file %s %t
+
+; RUN: not llvm-as < %t/not_a_constant.ll -o /dev/null 2>&1 | FileCheck -check-prefix=NOT_A_CONSTANT %s
+; RUN: not llvm-as < %t/not_a_sclar.ll -o /dev/null 2>&1 | FileCheck -check-prefix=NOT_A_SCALAR %s
+; RUN: not llvm-as < %t/not_a_vector.ll -o /dev/null 2>&1 | FileCheck -check-prefix=NOT_A_VECTOR %s
+; RUN: not llvm-as < %t/wrong_explicit_type.ll -o /dev/null 2>&1 | FileCheck -check-prefix=WRONG_EXPLICIT_TYPE %s
+; RUN: not llvm-as < %t/wrong_implicit_type.ll -o /dev/null 2>&1 | FileCheck -check-prefix=WRONG_IMPLICIT_TYPE %s
+
+;--- not_a_constant.ll
+; NOT_A_CONSTANT: error: expected instruction opcode
+define <4 x i32> @not_a_constant(i32 %a) {
+ %splat = splat (i32 %a)
+ ret <vscale x 4 x i32> %splat
+}
+
+;--- not_a_sclar.ll
+; NOT_A_SCALAR: error: constant expression type mismatch: got type '<1 x i32>' but expected 'i32'
+define <4 x i32> @not_a_scalar() {
+ ret <4 x i32> splat (<1 x i32> <i32 7>)
+}
+
+;--- not_a_vector.ll
+; NOT_A_VECTOR: error: vector constant must have vector type
+define <4 x i32> @not_a_vector() {
+ ret i32 splat (i32 7)
+}
+
+;--- wrong_explicit_type.ll
+; WRONG_EXPLICIT_TYPE: error: constant expression type mismatch: got type 'i8' but expected 'i32'
+define <4 x i32> @wrong_explicit_type() {
+ ret <4 x i32> splat (i8 7)
+}
+
+;--- wrong_implicit_type.ll
+; WRONG_IMPLICIT_TYPE: error: constant expression type mismatch: got type 'i8' but expected 'i32'
+define void @wrong_implicit_type(<4 x i32> %a) {
+ %add = add <4 x i32> %a, splat (i8 7)
+ ret void
+}
+
diff --git a/llvm/test/Assembler/constant-splat.ll b/llvm/test/Assembler/constant-splat.ll
new file mode 100644
index 0000000000000..f3ec0c8340aa1
--- /dev/null
+++ b/llvm/test/Assembler/constant-splat.ll
@@ -0,0 +1,67 @@
+; RUN: llvm-as < %s | llvm-dis | llvm-as | llvm-dis | FileCheck %s
+
+; NOTE: Tests the expansion of the "splat" shorthand method to create vector
+; constants. Future work will change how "splat" is expanded, ultimately
+; leading to a point where "splat" is emitted as the disassembly.
+
+ at my_global = external global i32
+
+; CHECK: @constant.splat.i1 = constant <1 x i1> <i1 true>
+ at constant.splat.i1 = constant <1 x i1> splat (i1 true)
+
+; CHECK: @constant.splat.i32 = constant <5 x i32> <i32 7, i32 7, i32 7, i32 7, i32 7>
+ at constant.splat.i32 = constant <5 x i32> splat (i32 7)
+
+; CHECK: @constant.splat.i128 = constant <2 x i128> <i128 85070591730234615870450834276742070272, i128 85070591730234615870450834276742070272>
+ at constant.splat.i128 = constant <2 x i128> splat (i128 85070591730234615870450834276742070272)
+
+; CHECK: @constant.splat.f16 = constant <4 x half> <half 0xHBC00, half 0xHBC00, half 0xHBC00, half 0xHBC00>
+ at constant.splat.f16 = constant <4 x half> splat (half 0xHBC00)
+
+; CHECK: @constant.splat.f32 = constant <5 x float> <float -2.000000e+00, float -2.000000e+00, float -2.000000e+00, float -2.000000e+00, float -2.000000e+00>
+ at constant.splat.f32 = constant <5 x float> splat (float -2.000000e+00)
+
+; CHECK: @constant.splat.f64 = constant <3 x double> <double -3.000000e+00, double -3.000000e+00, double -3.000000e+00>
+ at constant.splat.f64 = constant <3 x double> splat (double -3.000000e+00)
+
+; CHECK: @constant.splat.128 = constant <2 x fp128> <fp128 0xL00000000000000018000000000000000, fp128 0xL00000000000000018000000000000000>
+ at constant.splat.128 = constant <2 x fp128> splat (fp128 0xL00000000000000018000000000000000)
+
+; CHECK: @constant.splat.bf16 = constant <4 x bfloat> <bfloat 0xRC0A0, bfloat 0xRC0A0, bfloat 0xRC0A0, bfloat 0xRC0A0>
+ at constant.splat.bf16 = constant <4 x bfloat> splat (bfloat 0xRC0A0)
+
+; CHECK: @constant.splat.x86_fp80 = constant <3 x x86_fp80> <x86_fp80 0xK4000C8F5C28F5C28F800, x86_fp80 0xK4000C8F5C28F5C28F800, x86_fp80 0xK4000C8F5C28F5C28F800>
+ at constant.splat.x86_fp80 = constant <3 x x86_fp80> splat (x86_fp80 0xK4000C8F5C28F5C28F800)
+
+; CHECK: @constant.splat.ppc_fp128 = constant <1 x ppc_fp128> <ppc_fp128 0xM80000000000000000000000000000000>
+ at constant.splat.ppc_fp128 = constant <1 x ppc_fp128> splat (ppc_fp128 0xM80000000000000000000000000000000)
+
+; CHECK: @constant.splat.global.ptr = constant <4 x ptr> <ptr @my_global, ptr @my_global, ptr @my_global, ptr @my_global>
+ at constant.splat.global.ptr = constant <4 x ptr> splat (ptr @my_global)
+
+define void @add_fixed_lenth_vector_splat_i32(<4 x i32> %a) {
+; CHECK: %add = add <4 x i32> %a, <i32 137, i32 137, i32 137, i32 137>
+ %add = add <4 x i32> %a, splat (i32 137)
+ ret void
+}
+
+define <4 x i32> @ret_fixed_lenth_vector_splat_i32() {
+; CHECK: ret <4 x i32> <i32 56, i32 56, i32 56, i32 56>
+ ret <4 x i32> splat (i32 56)
+}
+
+define void @add_fixed_lenth_vector_splat_double(<vscale x 2 x double> %a) {
+; CHECK: %add = fadd <vscale x 2 x double> %a, shufflevector (<vscale x 2 x double> insertelement (<vscale x 2 x double> poison, double 5.700000e+00, i64 0), <vscale x 2 x double> poison, <vscale x 2 x i32> zeroinitializer)
+ %add = fadd <vscale x 2 x double> %a, splat (double 5.700000e+00)
+ ret void
+}
+
+define <vscale x 4 x i32> @ret_scalable_vector_splat_i32() {
+; CHECK: ret <vscale x 4 x i32> shufflevector (<vscale x 4 x i32> insertelement (<vscale x 4 x i32> poison, i32 78, i64 0), <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer)
+ ret <vscale x 4 x i32> splat (i32 78)
+}
+
+define <vscale x 4 x ptr> @ret_scalable_vector_ptr() {
+; CHECK: ret <vscale x 4 x ptr> shufflevector (<vscale x 4 x ptr> insertelement (<vscale x 4 x ptr> poison, ptr @my_global, i64 0), <vscale x 4 x ptr> poison, <vscale x 4 x i32> zeroinitializer)
+ ret <vscale x 4 x ptr> splat (ptr @my_global)
+}
More information about the llvm-commits
mailing list