llvm-mirror/test/Transforms/Scalarizer/scatter-order.ll
Bjorn Pettersson 651fd597ec [Scalarizer] Fix a non-deterministic scatter order problem
Summary:
The indexing operator in Scatterer may result in building new
instructions. When using multiple such operators in a function
argument list the order in which we build instructions depend on
argument evaluation order (which is undefined in C++).
This patch avoid such problems by expanding the components using
the [] operator prior to the function call.

Problem was seen when comparing output, while builing LLVM with
different compilers (clang vs gcc).

Reviewers: foad, cameron.mcinally, uabelho

Reviewed By: foad

Subscribers: hiraditya, mgrang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D78455
2020-04-20 16:05:33 +02:00

77 lines
3.8 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt %s -scalarizer -scalarize-load-store -S | FileCheck %s
; RUN: opt %s -passes='function(scalarizer)' -scalarize-load-store -S | FileCheck %s
; This verifies that the order of extract element instructions is
; deterministic. In the past we could end up with different results depending
; on the compiler used (due to argument evaluation order being undefined in
; C++). The order of the extracts is not really important for correctness of
; the result, but when debugging and creating test cases it is helpful if we
; get the same out put regardless of which compiler we use when building the
; compiler.
define <2 x i32> @test1(i1 %b, <2 x i32> %i, <2 x i32> %j) {
; CHECK-LABEL: @test1(
; CHECK-NEXT: [[I_I0:%.*]] = extractelement <2 x i32> [[I:%.*]], i32 0
; CHECK-NEXT: [[J_I0:%.*]] = extractelement <2 x i32> [[J:%.*]], i32 0
; CHECK-NEXT: [[RES_I0:%.*]] = select i1 [[B:%.*]], i32 [[I_I0]], i32 [[J_I0]]
; CHECK-NEXT: [[I_I1:%.*]] = extractelement <2 x i32> [[I]], i32 1
; CHECK-NEXT: [[J_I1:%.*]] = extractelement <2 x i32> [[J]], i32 1
; CHECK-NEXT: [[RES_I1:%.*]] = select i1 [[B]], i32 [[I_I1]], i32 [[J_I1]]
; CHECK-NEXT: [[RES_UPTO0:%.*]] = insertelement <2 x i32> undef, i32 [[RES_I0]], i32 0
; CHECK-NEXT: [[RES:%.*]] = insertelement <2 x i32> [[RES_UPTO0]], i32 [[RES_I1]], i32 1
; CHECK-NEXT: ret <2 x i32> [[RES]]
;
%res = select i1 %b, <2 x i32> %i, <2 x i32> %j
ret <2 x i32> %res
}
define <2 x i32> @test2(<2 x i1> %b, <2 x i32> %i, <2 x i32> %j) {
; CHECK-LABEL: @test2(
; CHECK-NEXT: [[B_I0:%.*]] = extractelement <2 x i1> [[B:%.*]], i32 0
; CHECK-NEXT: [[I_I0:%.*]] = extractelement <2 x i32> [[I:%.*]], i32 0
; CHECK-NEXT: [[J_I0:%.*]] = extractelement <2 x i32> [[J:%.*]], i32 0
; CHECK-NEXT: [[RES_I0:%.*]] = select i1 [[B_I0]], i32 [[I_I0]], i32 [[J_I0]]
; CHECK-NEXT: [[B_I1:%.*]] = extractelement <2 x i1> [[B]], i32 1
; CHECK-NEXT: [[I_I1:%.*]] = extractelement <2 x i32> [[I]], i32 1
; CHECK-NEXT: [[J_I1:%.*]] = extractelement <2 x i32> [[J]], i32 1
; CHECK-NEXT: [[RES_I1:%.*]] = select i1 [[B_I1]], i32 [[I_I1]], i32 [[J_I1]]
; CHECK-NEXT: [[RES_UPTO0:%.*]] = insertelement <2 x i32> undef, i32 [[RES_I0]], i32 0
; CHECK-NEXT: [[RES:%.*]] = insertelement <2 x i32> [[RES_UPTO0]], i32 [[RES_I1]], i32 1
; CHECK-NEXT: ret <2 x i32> [[RES]]
;
%res = select <2 x i1> %b, <2 x i32> %i, <2 x i32> %j
ret <2 x i32> %res
}
define <2 x i32> @test3(<2 x i32> %i, <2 x i32> %j) {
; CHECK-LABEL: @test3(
; CHECK-NEXT: [[I_I0:%.*]] = extractelement <2 x i32> [[I:%.*]], i32 0
; CHECK-NEXT: [[J_I0:%.*]] = extractelement <2 x i32> [[J:%.*]], i32 0
; CHECK-NEXT: [[RES_I0:%.*]] = add nuw nsw i32 [[I_I0]], [[J_I0]]
; CHECK-NEXT: [[I_I1:%.*]] = extractelement <2 x i32> [[I]], i32 1
; CHECK-NEXT: [[J_I1:%.*]] = extractelement <2 x i32> [[J]], i32 1
; CHECK-NEXT: [[RES_I1:%.*]] = add nuw nsw i32 [[I_I1]], [[J_I1]]
; CHECK-NEXT: [[RES_UPTO0:%.*]] = insertelement <2 x i32> undef, i32 [[RES_I0]], i32 0
; CHECK-NEXT: [[RES:%.*]] = insertelement <2 x i32> [[RES_UPTO0]], i32 [[RES_I1]], i32 1
; CHECK-NEXT: ret <2 x i32> [[RES]]
;
%res = add nuw nsw <2 x i32> %i, %j
ret <2 x i32> %res
}
define void @test4(<2 x i32>* %ptr, <2 x i32> %val) {
; CHECK-LABEL: @test4(
; CHECK-NEXT: [[VAL_I0:%.*]] = extractelement <2 x i32> [[VAL:%.*]], i32 0
; CHECK-NEXT: [[PTR_I0:%.*]] = bitcast <2 x i32>* [[PTR:%.*]] to i32*
; CHECK-NEXT: store i32 [[VAL_I0]], i32* [[PTR_I0]], align 8
; CHECK-NEXT: [[VAL_I1:%.*]] = extractelement <2 x i32> [[VAL]], i32 1
; CHECK-NEXT: [[PTR_I1:%.*]] = getelementptr i32, i32* [[PTR_I0]], i32 1
; CHECK-NEXT: store i32 [[VAL_I1]], i32* [[PTR_I1]], align 4
; CHECK-NEXT: ret void
;
store <2 x i32> %val, <2 x i32> *%ptr
ret void
}