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[SCEV] recognize llvm.annotation intrinsic 

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D127835
This commit is contained in:
Chen Zheng 2022-06-29 05:21:04 -04:00
parent f7a80c3d08
commit 2c3784cff8
3 changed files with 18 additions and 10 deletions
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16
llvm/docs/LangRef.rst
View File

@ -23575,8 +23575,10 @@ Semantics:
This intrinsic allows annotation of a pointer to an integer with arbitrary
strings. This can be useful for special purpose optimizations that want to look
for these annotations. These have no other defined use; they are ignored by code
generation and optimization.
for these annotations. These have no other defined use; transformations preserve
annotations on a best-effort basis but are allowed to replace the intrinsic with
its first argument without breaking semantics and the intrinsic is completely
dropped during instruction selection.
'``llvm.annotation.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -23611,10 +23613,12 @@ the line number. It returns the value of the first argument.
Semantics:
""""""""""
This intrinsic allows annotations to be put on arbitrary expressions
with arbitrary strings. This can be useful for special purpose
optimizations that want to look for these annotations. These have no
other defined use; they are ignored by code generation and optimization.
This intrinsic allows annotations to be put on arbitrary expressions with
arbitrary strings. This can be useful for special purpose optimizations that
want to look for these annotations. These have no other defined use;
transformations preserve annotations on a best-effort basis but are allowed to
replace the intrinsic with its first argument without breaking semantics and the
intrinsic is completely dropped during instruction selection.
'``llvm.codeview.annotation``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

8
llvm/lib/Analysis/ScalarEvolution.cpp
View File

@ -7365,6 +7365,8 @@ ScalarEvolution::getOperandsToCreate(Value *V, SmallVectorImpl<Value *> &Ops) {
Ops.push_back(II->getArgOperand(1));
return nullptr;
case Intrinsic::start_loop_iterations:
case Intrinsic::annotation:
case Intrinsic::ptr_annotation:
Ops.push_back(II->getArgOperand(0));
return nullptr;
default:
@ -7816,8 +7818,10 @@ const SCEV *ScalarEvolution::createSCEV(Value *V) {
return getAddExpr(ClampedX, Y, SCEV::FlagNUW);
}
case Intrinsic::start_loop_iterations:
// A start_loop_iterations is just equivalent to the first operand for
// SCEV purposes.
case Intrinsic::annotation:
case Intrinsic::ptr_annotation:
// A start_loop_iterations or llvm.annotation or llvm.prt.annotation is
// just eqivalent to the first operand for SCEV purposes.
return getSCEV(II->getArgOperand(0));
default:
break;

4
llvm/test/Analysis/ScalarEvolution/annotation-intrinsics.ll
View File

@ -8,7 +8,7 @@ define i64 @annotation(i64 %x) {
; CHECK-LABEL: 'annotation'
; CHECK-NEXT: Classifying expressions for: @annotation
; CHECK-NEXT: %1 = tail call i64 @llvm.annotation.i64(i64 %x, i8* null, i8* null, i32 0)
; CHECK-NEXT: --> %1 U: full-set S: full-set
; CHECK-NEXT: --> %x U: full-set S: full-set
; CHECK-NEXT: Determining loop execution counts for: @annotation
;
%1 = tail call i64 @llvm.annotation.i64(i64 %x, i8* null, i8* null, i32 0)
@ -19,7 +19,7 @@ define i8* @ptr_annotation(i8* %x) {
; CHECK-LABEL: 'ptr_annotation'
; CHECK-NEXT: Classifying expressions for: @ptr_annotation
; CHECK-NEXT: %1 = call i8* @llvm.ptr.annotation.p0i8(i8* %x, i8* null, i8* null, i32 0, i8* null)
; CHECK-NEXT: --> %1 U: full-set S: full-set
; CHECK-NEXT: --> %x U: full-set S: full-set
; CHECK-NEXT: Determining loop execution counts for: @ptr_annotation
;
%1 = call i8* @llvm.ptr.annotation.p0i8(i8* %x, i8* null, i8* null, i32 0, i8* null)