Look through addrspacecasts when turning ptr comparisons into

index comparisons.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210488 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matt Arsenault 2014-06-09 19:20:29 +00:00
parent 77b0b852fa
commit 8a0c2d17f5
2 changed files with 65 additions and 7 deletions

View File

@ -612,9 +612,10 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
if (ICmpInst::isSigned(Cond))
return nullptr;
// Look through bitcasts.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(RHS))
RHS = BCI->getOperand(0);
// Look through bitcasts and addrspacecasts. We do not however want to remove
// 0 GEPs.
if (!isa<GetElementPtrInst>(RHS))
RHS = RHS->stripPointerCasts();
Value *PtrBase = GEPLHS->getOperand(0);
if (DL && PtrBase == RHS && GEPLHS->isInBounds()) {
@ -655,9 +656,24 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
(GEPRHS->hasAllConstantIndices() || GEPRHS->hasOneUse()) &&
PtrBase->stripPointerCasts() ==
GEPRHS->getOperand(0)->stripPointerCasts()) {
Value *LOffset = EmitGEPOffset(GEPLHS);
Value *ROffset = EmitGEPOffset(GEPRHS);
// If we looked through an addrspacecast between different sized address
// spaces, the LHS and RHS pointers are different sized
// integers. Truncate to the smaller one.
Type *LHSIndexTy = LOffset->getType();
Type *RHSIndexTy = ROffset->getType();
if (LHSIndexTy != RHSIndexTy) {
if (LHSIndexTy->getPrimitiveSizeInBits() <
RHSIndexTy->getPrimitiveSizeInBits()) {
ROffset = Builder->CreateTrunc(ROffset, LHSIndexTy);
} else
LOffset = Builder->CreateTrunc(LOffset, RHSIndexTy);
}
Value *Cmp = Builder->CreateICmp(ICmpInst::getSignedPredicate(Cond),
EmitGEPOffset(GEPLHS),
EmitGEPOffset(GEPRHS));
LOffset, ROffset);
return ReplaceInstUsesWith(I, Cmp);
}

View File

@ -1,7 +1,6 @@
; RUN: opt < %s -instcombine -S | FileCheck %s
target datalayout =
"e-p:64:64:64-p1:16:16:16-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 datalayout = "e-p:64:64:64-p1:16:16:16-p2:32:32:32-p3:64:64:64-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"
define i32 @test1(i32 %X) {
entry:
@ -674,6 +673,49 @@ define i1 @test60_as1(i8 addrspace(1)* %foo, i64 %i, i64 %j) {
; CHECK-NEXT: ret i1
}
; Same as test60, but look through an addrspacecast instead of a
; bitcast. This uses the same sized addrspace.
define i1 @test60_addrspacecast(i8* %foo, i64 %i, i64 %j) {
%bit = addrspacecast i8* %foo to i32 addrspace(3)*
%gep1 = getelementptr inbounds i32 addrspace(3)* %bit, i64 %i
%gep2 = getelementptr inbounds i8* %foo, i64 %j
%cast1 = addrspacecast i32 addrspace(3)* %gep1 to i8*
%cmp = icmp ult i8* %cast1, %gep2
ret i1 %cmp
; CHECK-LABEL: @test60_addrspacecast(
; CHECK-NEXT: %gep1.idx = shl nuw i64 %i, 2
; CHECK-NEXT: icmp slt i64 %gep1.idx, %j
; CHECK-NEXT: ret i1
}
define i1 @test60_addrspacecast_smaller(i8* %foo, i16 %i, i64 %j) {
%bit = addrspacecast i8* %foo to i32 addrspace(1)*
%gep1 = getelementptr inbounds i32 addrspace(1)* %bit, i16 %i
%gep2 = getelementptr inbounds i8* %foo, i64 %j
%cast1 = addrspacecast i32 addrspace(1)* %gep1 to i8*
%cmp = icmp ult i8* %cast1, %gep2
ret i1 %cmp
; CHECK-LABEL: @test60_addrspacecast_smaller(
; CHECK-NEXT: %gep1.idx = shl nuw i16 %i, 2
; CHECK-NEXT: trunc i64 %j to i16
; CHECK-NEXT: icmp sgt i16 %1, %gep1.idx
; CHECK-NEXT: ret i1
}
define i1 @test60_addrspacecast_larger(i8 addrspace(1)* %foo, i32 %i, i16 %j) {
%bit = addrspacecast i8 addrspace(1)* %foo to i32 addrspace(2)*
%gep1 = getelementptr inbounds i32 addrspace(2)* %bit, i32 %i
%gep2 = getelementptr inbounds i8 addrspace(1)* %foo, i16 %j
%cast1 = addrspacecast i32 addrspace(2)* %gep1 to i8 addrspace(1)*
%cmp = icmp ult i8 addrspace(1)* %cast1, %gep2
ret i1 %cmp
; CHECK-LABEL: @test60_addrspacecast_larger(
; CHECK-NEXT: %gep1.idx = shl nuw i32 %i, 2
; CHECK-NEXT: trunc i32 %gep1.idx to i16
; CHECK-NEXT: icmp slt i16 %1, %j
; CHECK-NEXT: ret i1
}
define i1 @test61(i8* %foo, i64 %i, i64 %j) {
%bit = bitcast i8* %foo to i32*
%gep1 = getelementptr i32* %bit, i64 %i