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[MergeICmps] Don't merge icmps derived from pointers with addressspaces 

IIUC we can't emit `memcmp` between pointers in addressspaces,
doing so will trigger an assertion since the signature of the memcmp
will not match it's arguments (https://bugs.llvm.org/show_bug.cgi?id=48661).

This PR disables the attempt to merge icmps,
when the pointer is in an addressspace.

Reviewed By: #julialang, vtjnash

Differential Revision: https://reviews.llvm.org/D94813
This commit is contained in:
Valentin Churavy 2021-08-27 17:20:14 +02:00
parent 1b05245119
commit 4cacb5cad0
No known key found for this signature in database
GPG Key ID: 02E09F0CCD46FF9D
2 changed files with 98 additions and 0 deletions
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4
llvm/lib/Transforms/Scalar/MergeICmps.cpp
View File

@ -145,6 +145,10 @@ BCEAtom visitICmpLoadOperand(Value *const Val, BaseIdentifier &BaseId) {
return {};
}
Value *const Addr = LoadI->getOperand(0);
if (Addr->getType()->getPointerAddressSpace() != 0) {
LLVM_DEBUG(dbgs() << "from non-zero AddressSpace\n");
return {};
}
auto *const GEP = dyn_cast<GetElementPtrInst>(Addr);
if (!GEP)
return {};

94
llvm/test/Transforms/MergeICmps/X86/addressspaces.ll Normal file
View File

@ -0,0 +1,94 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -S -mergeicmps -verify-dom-info | FileCheck %s
target triple = "x86_64"
; First check that we try to from a memcmp.
define void @form_memcmp([2 x i64]* dereferenceable(16) %a, [2 x i64]* dereferenceable(16) %b) {
; CHECK-LABEL: @form_memcmp(
; CHECK-NEXT: bb0:
; CHECK-NEXT: [[PTR_A0:%.*]] = getelementptr inbounds [2 x i64], [2 x i64]* [[A:%.*]], i64 0, i64 0
; CHECK-NEXT: [[PTR_A1:%.*]] = getelementptr inbounds [2 x i64], [2 x i64]* [[A]], i64 0, i64 1
; CHECK-NEXT: [[PTR_B0:%.*]] = getelementptr inbounds [2 x i64], [2 x i64]* [[B:%.*]], i64 0, i64 0
; CHECK-NEXT: [[PTR_B1:%.*]] = getelementptr inbounds [2 x i64], [2 x i64]* [[B]], i64 0, i64 1
; CHECK-NEXT: br label %"bb1+bb2"
; CHECK: "bb1+bb2":
; CHECK-NEXT: [[TMP0:%.*]] = getelementptr inbounds [2 x i64], [2 x i64]* [[A]], i64 0, i64 0
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds [2 x i64], [2 x i64]* [[B]], i64 0, i64 0
; CHECK-NEXT: [[CSTR:%.*]] = bitcast i64* [[TMP0]] to i8*
; CHECK-NEXT: [[CSTR1:%.*]] = bitcast i64* [[TMP1]] to i8*
; CHECK-NEXT: [[MEMCMP:%.*]] = call i32 @memcmp(i8* [[CSTR]], i8* [[CSTR1]], i64 16)
; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i32 [[MEMCMP]], 0
; CHECK-NEXT: br label [[BB3:%.*]]
; CHECK: bb3:
; CHECK-NEXT: ret void
;
bb0:
%ptr_a0 = getelementptr inbounds [2 x i64], [2 x i64]* %a, i64 0, i64 0
%ptr_a1 = getelementptr inbounds [2 x i64], [2 x i64]* %a, i64 0, i64 1
%ptr_b0 = getelementptr inbounds [2 x i64], [2 x i64]* %b, i64 0, i64 0
%ptr_b1 = getelementptr inbounds [2 x i64], [2 x i64]* %b, i64 0, i64 1
br label %bb1
bb1: ; preds = %bb0
%a0 = load i64, i64* %ptr_a0
%b0 = load i64, i64* %ptr_b0
%cond0 = icmp eq i64 %a0, %b0
br i1 %cond0, label %bb2, label %bb3
bb2: ; preds = %bb1
%a1 = load i64, i64* %ptr_a1
%b1 = load i64, i64* %ptr_b1
%cond1 = icmp eq i64 %a1, %b1
br label %bb3
bb3: ; preds = %bb2, %bb1
%necessary = phi i1 [ %cond1, %bb2 ], [ false, %bb1 ]
ret void
}
; We can't use memcmp between arbitrary addressesspaces
define void @no_memcmp([2 x i64] addrspace(11)* dereferenceable(16) %a, [2 x i64] addrspace(11)* dereferenceable(16) %b) {
; CHECK-LABEL: @no_memcmp(
; CHECK-NEXT: bb0:
; CHECK-NEXT: [[PTR_A0:%.*]] = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* [[A:%.*]], i64 0, i64 0
; CHECK-NEXT: [[PTR_A1:%.*]] = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* [[A]], i64 0, i64 1
; CHECK-NEXT: [[PTR_B0:%.*]] = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* [[B:%.*]], i64 0, i64 0
; CHECK-NEXT: [[PTR_B1:%.*]] = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* [[B]], i64 0, i64 1
; CHECK-NEXT: br label [[BB1:%.*]]
; CHECK: bb1:
; CHECK-NEXT: [[A0:%.*]] = load i64, i64 addrspace(11)* [[PTR_A0]], align 4
; CHECK-NEXT: [[B0:%.*]] = load i64, i64 addrspace(11)* [[PTR_B0]], align 4
; CHECK-NEXT: [[COND0:%.*]] = icmp eq i64 [[A0]], [[B0]]
; CHECK-NEXT: br i1 [[COND0]], label [[BB2:%.*]], label [[BB3:%.*]]
; CHECK: bb2:
; CHECK-NEXT: [[A1:%.*]] = load i64, i64 addrspace(11)* [[PTR_A1]], align 4
; CHECK-NEXT: [[B1:%.*]] = load i64, i64 addrspace(11)* [[PTR_B1]], align 4
; CHECK-NEXT: [[COND1:%.*]] = icmp eq i64 [[A1]], [[B1]]
; CHECK-NEXT: br label [[BB3]]
; CHECK: bb3:
; CHECK-NEXT: [[NECESSARY:%.*]] = phi i1 [ [[COND1]], [[BB2]] ], [ false, [[BB1]] ]
; CHECK-NEXT: ret void
;
bb0:
%ptr_a0 = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* %a, i64 0, i64 0
%ptr_a1 = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* %a, i64 0, i64 1
%ptr_b0 = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* %b, i64 0, i64 0
%ptr_b1 = getelementptr inbounds [2 x i64], [2 x i64] addrspace(11)* %b, i64 0, i64 1
br label %bb1
bb1: ; preds = %bb0
%a0 = load i64, i64 addrspace(11)* %ptr_a0
%b0 = load i64, i64 addrspace(11)* %ptr_b0
%cond0 = icmp eq i64 %a0, %b0
br i1 %cond0, label %bb2, label %bb3
bb2: ; preds = %bb1
%a1 = load i64, i64 addrspace(11)* %ptr_a1
%b1 = load i64, i64 addrspace(11)* %ptr_b1
%cond1 = icmp eq i64 %a1, %b1
br label %bb3
bb3: ; preds = %bb2, %bb1
%necessary = phi i1 [ %cond1, %bb2 ], [ false, %bb1 ]
ret void
}