[IROutliner] Adding consistent function attribute merging

When combining extracted functions, they may have different function
attributes. We want to make sure that we do not make any assumptions,
or lose any information. This attempts to make sure that we consolidate
function attributes to their most general case.

Tests:
llvm/test/Transforms/IROutliner/outlining-compatible-and-attribute-transfer.ll
llvm/test/Transforms/IROutliner/outlining-compatible-or-attribute-transfer.ll

Reviewers: jdoefert, paquette

Differential Revision: https://reviews.llvm.org/D87301

diff --git a/llvm/include/llvm/IR/Attributes.h b/llvm/include/llvm/IR/Attributes.h
index bf95959..fbfe585 100644 (file)
--- a/llvm/include/llvm/IR/Attributes.h
+++ b/llvm/include/llvm/IR/Attributes.h
@@ -951,9 +951,24 @@ AttrBuilder typeIncompatible(Type *Ty);
 /// attributes for inlining purposes.
 bool areInlineCompatible(const Function &Caller, const Function &Callee);
 
+
+/// Checks  if there are any incompatible function attributes between
+/// \p A and \p B.
+///
+/// \param [in] A - The first function to be compared with.
+/// \param [in] B - The second function to be compared with.
+/// \returns true if the functions have compatible attributes.
+bool areOutlineCompatible(const Function &A, const Function &B);
+
 /// Merge caller's and callee's attributes.
 void mergeAttributesForInlining(Function &Caller, const Function &Callee);
 
+/// Merges the functions attributes from \p ToMerge into function \p Base.
+///
+/// \param [in,out] Base - The function being merged into.
+/// \param [in] ToMerge - The function to merge attributes from.
+void mergeAttributesForOutlining(Function &Base, const Function &ToMerge);
+
 } // end namespace AttributeFuncs
 
 } // end namespace llvm

diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
index 7001ab8..d39cdf7 100644 (file)
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -2091,7 +2091,25 @@ bool AttributeFuncs::areInlineCompatible(const Function &Caller,
   return hasCompatibleFnAttrs(Caller, Callee);
 }
 
+bool AttributeFuncs::areOutlineCompatible(const Function &A,
+                                          const Function &B) {
+  return hasCompatibleFnAttrs(A, B);
+}
+
 void AttributeFuncs::mergeAttributesForInlining(Function &Caller,
                                                 const Function &Callee) {
   mergeFnAttrs(Caller, Callee);
 }
+
+void AttributeFuncs::mergeAttributesForOutlining(Function &Base,
+                                                const Function &ToMerge) {
+
+  // We merge functions so that they meet the most general case.
+  // For example, if the NoNansFPMathAttr is set in one function, but not in
+  // the other, in the merged function we can say that the NoNansFPMathAttr
+  // is not set.
+  // However if we have the SpeculativeLoadHardeningAttr set true in one
+  // function, but not the other, we make sure that the function retains
+  // that aspect in the merged function.
+  mergeFnAttrs(Base, ToMerge);
+}

diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
index 908ba0c..0160576 100644 (file)
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -1201,6 +1201,8 @@ void IROutliner::deduplicateExtractedSections(
 
   for (unsigned Idx = 1; Idx < CurrentGroup.Regions.size(); Idx++) {
     CurrentOS = CurrentGroup.Regions[Idx];
+    AttributeFuncs::mergeAttributesForOutlining(*CurrentGroup.OutlinedFunction,
+                                               *CurrentOS->ExtractedFunction);
 
     // Create a new BasicBlock to hold the needed store instructions.
     BasicBlock *NewBB = BasicBlock::Create(

diff --git a/llvm/test/Transforms/IROutliner/outlining-compatible-and-attribute-transfer.ll b/llvm/test/Transforms/IROutliner/outlining-compatible-and-attribute-transfer.ll
new file mode 100644 (file)
index 0000000..0a05188
--- /dev/null
+++ b/llvm/test/Transforms/IROutliner/outlining-compatible-and-attribute-transfer.ll
@@ -0,0 +1,126 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -verify -iroutliner < %s | FileCheck %s
+
+; This has two compatible regions based on function attributes.  We have
+; attributes that should be transferred only if it is on all of the regions.
+
+; This includes the attributes, no-nans-fp-math,
+; no-signed-zeros-fp-math, less-precise-fpmad, unsafe-fp-math, and 
+; no-infs-fp-math.  Only when each instance of similarity has these attributes
+; can we say that the outlined function can have these attributes since that
+; is the more general case for these attributes.
+
+define void @outline_attrs1() #0 {
+; CHECK-LABEL: @outline_attrs1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_1(i32* [[A]], i32* [[B]], i32* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+define void @outline_attrs2() #0 {
+; CHECK-LABEL: @outline_attrs2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_1(i32* [[A]], i32* [[B]], i32* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+define void @outline_attrs3() #0 {
+; CHECK-LABEL: @outline_attrs3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca float, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca float, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca float, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(float* [[A]], float* [[B]], float* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca float, align 4
+  %b = alloca float, align 4
+  %c = alloca float, align 4
+  store float 2.0, float* %a, align 4
+  store float 3.0, float* %b, align 4
+  store float 4.0, float* %c, align 4
+  %al = load float, float* %a
+  %bl = load float, float* %b
+  %cl = load float, float* %c
+  %0 = fmul float %al, %bl
+  ret void
+}
+
+define void @outline_attrs4() {
+; CHECK-LABEL: @outline_attrs4(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca float, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca float, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca float, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(float* [[A]], float* [[B]], float* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca float, align 4
+  %b = alloca float, align 4
+  %c = alloca float, align 4
+  store float 2.0, float* %a, align 4
+  store float 3.0, float* %b, align 4
+  store float 4.0, float* %c, align 4
+  %al = load float, float* %a
+  %bl = load float, float* %b
+  %cl = load float, float* %c
+  %0 = fmul float %al, %bl
+  ret void
+}
+
+attributes #0 = { "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "less-precise-fpmad"="true"
+"unsafe-fp-math"="true" "no-infs-fp-math"="true"}
+
+; CHECK: define internal void @outlined_ir_func_0(float* [[ARG0:%.*]], float* [[ARG1:%.*]], float* [[ARG2:%.*]]) [[ATTR1:#[0-9]+]] {
+; CHECK: entry_to_outline:
+; CHECK-NEXT:    store float 2.000000e+00, float* [[ARG0]], align 4
+; CHECK-NEXT:    store float 3.000000e+00, float* [[ARG1]], align 4
+; CHECK-NEXT:    store float 4.000000e+00, float* [[ARG2]], align 4
+; CHECK-NEXT:    [[AL:%.*]] = load float, float* [[ARG0]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load float, float* [[ARG1]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load float, float* [[ARG2]], align 4
+
+; CHECK: define internal void @outlined_ir_func_1(i32* [[ARG0:%.*]], i32* [[ARG1:%.*]], i32* [[ARG2:%.*]]) [[ATTR:#[0-9]+]] {
+; CHECK: entry_to_outline:
+; CHECK-NEXT:    store i32 2, i32* [[ARG0]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[ARG1]], align 4
+; CHECK-NEXT:    store i32 4, i32* [[ARG2]], align 4
+; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[ARG0]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[ARG1]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[ARG2]], align 4
+
+
+; CHECK: attributes [[ATTR1]] =   { minsize optsize "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "unsafe-fp-math"="false" }
+; CHECK: attributes [[ATTR]] = { minsize optsize "less-precise-fpmad"="true" "no-infs-fp-math"="true" "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "unsafe-fp-math"="true" }

diff --git a/llvm/test/Transforms/IROutliner/outlining-compatible-or-attribute-transfer.ll b/llvm/test/Transforms/IROutliner/outlining-compatible-or-attribute-transfer.ll
new file mode 100644 (file)
index 0000000..2c1daa7
--- /dev/null
+++ b/llvm/test/Transforms/IROutliner/outlining-compatible-or-attribute-transfer.ll
@@ -0,0 +1,67 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -S -verify -iroutliner < "%s" | FileCheck "%s"
+
+; This has two compatible regions.  We have attributes that should be transferred 
+; even if it is on only one of the regions.
+
+; This includes the attributes no-jump-tables, profile-sample-accurate,
+; speculative_load_hardening, and noimplicitfloat.  When instance of similarity
+; has these attributes can we say that the outlined function can have these
+; attributes since that is the more general case.
+
+define void @outline_attrs1() #0 {
+; CHECK-LABEL: @outline_attrs1(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+define void @outline_attrs2() {
+; CHECK-LABEL: @outline_attrs2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[A:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[B:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    [[C:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @outlined_ir_func_0(i32* [[A]], i32* [[B]], i32* [[C]])
+; CHECK-NEXT:    ret void
+;
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  %c = alloca i32, align 4
+  store i32 2, i32* %a, align 4
+  store i32 3, i32* %b, align 4
+  store i32 4, i32* %c, align 4
+  %al = load i32, i32* %a
+  %bl = load i32, i32* %b
+  %cl = load i32, i32* %c
+  ret void
+}
+
+attributes #0 = { "no-jump-tables"="true" "profile-sample-accurate"="true" "speculative_load_hardening" "noimplicitfloat"="true" "use-sample-profile"="true"}
+
+; CHECK: define internal void @outlined_ir_func_0(i32* [[ARG0:%.*]], i32* [[ARG1:%.*]], i32* [[ARG2:%.*]]) [[ATTR:#[0-9]+]] {
+; CHECK: entry_to_outline:
+; CHECK-NEXT:    store i32 2, i32* [[ARG0]], align 4
+; CHECK-NEXT:    store i32 3, i32* [[ARG1]], align 4
+; CHECK-NEXT:    store i32 4, i32* [[ARG2]], align 4
+; CHECK-NEXT:    [[AL:%.*]] = load i32, i32* [[ARG0]], align 4
+; CHECK-NEXT:    [[BL:%.*]] = load i32, i32* [[ARG1]], align 4
+; CHECK-NEXT:    [[CL:%.*]] = load i32, i32* [[ARG2]], align 4
+
+; CHECK: attributes [[ATTR]] = { minsize optsize "no-jump-tables"="true" "noimplicitfloat"="true" "profile-sample-accurate"="true" "speculative_load_hardening" "use-sample-profile"="true" }