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[SLC] Dereferenceable annonation - handle valid null pointers 

Reviewers: jdoerfert, reames

Reviewed By: jdoerfert

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66161

llvm-svn: 368884
This commit is contained in:
David Bolvansky 2019-08-14 17:15:20 +00:00
parent 92541e359e
commit f94460d4b6
3 changed files with 34 additions and 5 deletions
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15
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
View File

@ -189,15 +189,22 @@ static bool canTransformToMemCmp(CallInst *CI, Value *Str, uint64_t Len,
static void annotateDereferenceableBytes(CallInst *CI,
ArrayRef<unsigned> ArgNos,
uint64_t DereferenceableBytes) {
const Function *F = CI->getFunction();
if (!F)
return;
for (unsigned ArgNo : ArgNos) {
uint64_t DerefBytes = std::max(
CI->getDereferenceableOrNullBytes(ArgNo + AttributeList::FirstArgIndex),
DereferenceableBytes);
uint64_t DerefBytes = DereferenceableBytes;
unsigned AS = CI->getArgOperand(ArgNo)->getType()->getPointerAddressSpace();
if (!llvm::NullPointerIsDefined(F, AS))
DerefBytes = std::max(CI->getDereferenceableOrNullBytes(
ArgNo + AttributeList::FirstArgIndex),
DereferenceableBytes);
if (CI->getDereferenceableBytes(ArgNo + AttributeList::FirstArgIndex) <
DerefBytes) {
CI->removeParamAttr(ArgNo, Attribute::Dereferenceable);
CI->removeParamAttr(ArgNo, Attribute::DereferenceableOrNull);
if (!llvm::NullPointerIsDefined(F, AS))
CI->removeParamAttr(ArgNo, Attribute::DereferenceableOrNull);
CI->addParamAttr(ArgNo, Attribute::getWithDereferenceableBytes(
CI->getContext(), DerefBytes));
}

13
llvm/test/Transforms/InstCombine/mem-deref-bytes-addrspaces.ll Normal file
View File

@ -0,0 +1,13 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -instcombine -S < %s | FileCheck %s
declare i32 @memcmp(i8 addrspace(1)* nocapture, i8* nocapture, i64)
define i32 @memcmp_const_size_update_deref8(i8 addrspace(1)* nocapture readonly %d, i8* nocapture readonly %s) {
; CHECK-LABEL: @memcmp_const_size_update_deref8(
; CHECK-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8 addrspace(1)* dereferenceable(16) dereferenceable_or_null(40) [[D:%.*]], i8* dereferenceable(16) [[S:%.*]], i64 16)
; CHECK-NEXT: ret i32 [[CALL]]
;
%call = tail call i32 @memcmp(i8 addrspace(1)* dereferenceable_or_null(40) %d, i8* %s, i64 16)
ret i32 %call
}

11
llvm/test/Transforms/InstCombine/mem-deref-bytes.ll
View File

@ -55,7 +55,7 @@ define i32 @memcmp_const_size_update_deref4(i8* nocapture readonly %d, i8* nocap
ret i32 %call
}
define i32 @memcmp_const_size_update_deref5(i8* nocapture readonly %d, i8* nocapture readonly %s) {
define i32 @memcmp_const_size_update_deref5(i8* nocapture readonly %d, i8* nocapture readonly %s) "null-pointer-is-valid"="false" {
; CHECK-LABEL: @memcmp_const_size_update_deref5(
; CHECK-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8* dereferenceable(40) [[D:%.*]], i8* dereferenceable(16) [[S:%.*]], i64 16)
; CHECK-NEXT: ret i32 [[CALL]]
@ -64,6 +64,15 @@ define i32 @memcmp_const_size_update_deref5(i8* nocapture readonly %d, i8* nocap
ret i32 %call
}
define i32 @memcmp_const_size_update_deref6(i8* nocapture readonly %d, i8* nocapture readonly %s) "null-pointer-is-valid"="true" {
; CHECK-LABEL: @memcmp_const_size_update_deref6(
; CHECK-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8* dereferenceable(16) dereferenceable_or_null(40) [[D:%.*]], i8* dereferenceable(16) [[S:%.*]], i64 16)
; CHECK-NEXT: ret i32 [[CALL]]
;
%call = tail call i32 @memcmp(i8* dereferenceable_or_null(40) %d, i8* %s, i64 16)
ret i32 %call
}
define i32 @memcmp_const_size_no_update_deref(i8* nocapture readonly %d, i8* nocapture readonly %s) {
; CHECK-LABEL: @memcmp_const_size_no_update_deref(
; CHECK-NEXT: [[CALL:%.*]] = tail call i32 @memcmp(i8* dereferenceable(40) [[D:%.*]], i8* dereferenceable(20) [[S:%.*]], i64 16)