mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-09-08 23:55:03 +00:00
Make Value::isDereferenceablePointer() handle unreachable code blocks. (This
returns false in the event the computation feeding into the pointer is unreachable, which maybe ought to be true -- but this is at least consistent with undef->isDereferenceablePointer().) Fixes PR11825! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148671 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
1906d32e55
commit
37abc488a0
@ -349,7 +349,8 @@ Value *Value::stripPointerCasts() {
|
|||||||
|
|
||||||
/// isDereferenceablePointer - Test if this value is always a pointer to
|
/// isDereferenceablePointer - Test if this value is always a pointer to
|
||||||
/// allocated and suitably aligned memory for a simple load or store.
|
/// allocated and suitably aligned memory for a simple load or store.
|
||||||
bool Value::isDereferenceablePointer() const {
|
static bool isDereferenceablePointer(const Value *V,
|
||||||
|
SmallPtrSet<const Value *, 32> &Visited) {
|
||||||
// Note that it is not safe to speculate into a malloc'd region because
|
// Note that it is not safe to speculate into a malloc'd region because
|
||||||
// malloc may return null.
|
// malloc may return null.
|
||||||
// It's also not always safe to follow a bitcast, for example:
|
// It's also not always safe to follow a bitcast, for example:
|
||||||
@ -358,20 +359,22 @@ bool Value::isDereferenceablePointer() const {
|
|||||||
// be handled using TargetData to check sizes and alignments though.
|
// be handled using TargetData to check sizes and alignments though.
|
||||||
|
|
||||||
// These are obviously ok.
|
// These are obviously ok.
|
||||||
if (isa<AllocaInst>(this)) return true;
|
if (isa<AllocaInst>(V)) return true;
|
||||||
|
|
||||||
// Global variables which can't collapse to null are ok.
|
// Global variables which can't collapse to null are ok.
|
||||||
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(this))
|
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V))
|
||||||
return !GV->hasExternalWeakLinkage();
|
return !GV->hasExternalWeakLinkage();
|
||||||
|
|
||||||
// byval arguments are ok.
|
// byval arguments are ok.
|
||||||
if (const Argument *A = dyn_cast<Argument>(this))
|
if (const Argument *A = dyn_cast<Argument>(V))
|
||||||
return A->hasByValAttr();
|
return A->hasByValAttr();
|
||||||
|
|
||||||
// For GEPs, determine if the indexing lands within the allocated object.
|
// For GEPs, determine if the indexing lands within the allocated object.
|
||||||
if (const GEPOperator *GEP = dyn_cast<GEPOperator>(this)) {
|
if (const GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
|
||||||
// Conservatively require that the base pointer be fully dereferenceable.
|
// Conservatively require that the base pointer be fully dereferenceable.
|
||||||
if (!GEP->getOperand(0)->isDereferenceablePointer())
|
if (!Visited.insert(GEP->getOperand(0)))
|
||||||
|
return false;
|
||||||
|
if (!isDereferenceablePointer(GEP->getOperand(0), Visited))
|
||||||
return false;
|
return false;
|
||||||
// Check the indices.
|
// Check the indices.
|
||||||
gep_type_iterator GTI = gep_type_begin(GEP);
|
gep_type_iterator GTI = gep_type_begin(GEP);
|
||||||
@ -405,6 +408,13 @@ bool Value::isDereferenceablePointer() const {
|
|||||||
return false;
|
return false;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
/// isDereferenceablePointer - Test if this value is always a pointer to
|
||||||
|
/// allocated and suitably aligned memory for a simple load or store.
|
||||||
|
bool Value::isDereferenceablePointer() const {
|
||||||
|
SmallPtrSet<const Value *, 32> Visited;
|
||||||
|
return ::isDereferenceablePointer(this, Visited);
|
||||||
|
}
|
||||||
|
|
||||||
/// DoPHITranslation - If this value is a PHI node with CurBB as its parent,
|
/// DoPHITranslation - If this value is a PHI node with CurBB as its parent,
|
||||||
/// return the value in the PHI node corresponding to PredBB. If not, return
|
/// return the value in the PHI node corresponding to PredBB. If not, return
|
||||||
/// ourself. This is useful if you want to know the value something has in a
|
/// ourself. This is useful if you want to know the value something has in a
|
||||||
|
28
test/Transforms/SimplifyCFG/unreachable-blocks.ll
Normal file
28
test/Transforms/SimplifyCFG/unreachable-blocks.ll
Normal file
@ -0,0 +1,28 @@
|
|||||||
|
; RUN: opt -simplifycfg < %s -disable-output
|
||||||
|
|
||||||
|
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
|
||||||
|
target triple = "x86_64-pc-linux-gnu"
|
||||||
|
|
||||||
|
; PR11825
|
||||||
|
define void @test1() {
|
||||||
|
entry:
|
||||||
|
br label %return
|
||||||
|
|
||||||
|
while_block: ; preds = %and_if_cont2, %and_if_cont
|
||||||
|
%newlen = sub i32 %newlen, 1
|
||||||
|
%newptr = getelementptr i8* %newptr, i64 1
|
||||||
|
%test = icmp sgt i32 %newlen, 0
|
||||||
|
br i1 %test, label %and_if1, label %and_if_cont2
|
||||||
|
|
||||||
|
and_if1: ; preds = %while_block
|
||||||
|
%char = load i8* %newptr
|
||||||
|
%test2 = icmp ule i8 %char, 32
|
||||||
|
br label %and_if_cont2
|
||||||
|
|
||||||
|
and_if_cont2: ; preds = %and_if1, %while_block
|
||||||
|
%a18 = phi i1 [ %test, %while_block ], [ %test2, %and_if1 ]
|
||||||
|
br i1 %a18, label %while_block, label %return
|
||||||
|
|
||||||
|
return: ; preds = %and_if_cont2, %and_if_cont
|
||||||
|
ret void
|
||||||
|
}
|
Loading…
Reference in New Issue
Block a user