llvm-6502/test/Transforms/SROA/alignment.ll
Chandler Carruth aa3cb334af Teach the integer-promotion rewrite strategy to be endianness aware.
Sorry for this being broken so long. =/

As part of this, switch all of the existing tests to be Little Endian,
which is the behavior I was asserting in them anyways! Add in a new
big-endian test that checks the interesting behavior there.

Another part of this is to tighten the rules abotu when we perform the
full-integer promotion. This logic now rejects cases where there fully
promoted integer is a non-multiple-of-8 bitwidth or cases where the
loads or stores touch bits which are in the allocated space of the
alloca but are not loaded or stored when accessing the integer. Sadly,
these aren't really observable today as the rest of the pass will
already ensure the invariants hold. However, the latter situation is
likely to become a potential concern in the future.

Thanks to Benjamin and Duncan for early review of this patch. I'm still
looking into whether there are further endianness issues, please let me
know if anyone sees BE failures persisting past this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165219 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-04 10:39:28 +00:00

203 lines
7.0 KiB
LLVM

; RUN: opt < %s -sroa -S | FileCheck %s
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n8:16:32:64"
declare void @llvm.memcpy.p0i8.p0i8.i32(i8*, i8*, i32, i32, i1)
define void @test1({ i8, i8 }* %a, { i8, i8 }* %b) {
; CHECK: @test1
; CHECK: %[[gep_a0:.*]] = getelementptr inbounds { i8, i8 }* %a, i64 0, i32 0
; CHECK: %[[a0:.*]] = load i8* %[[gep_a0]], align 16
; CHECK: %[[gep_a1:.*]] = getelementptr inbounds { i8, i8 }* %a, i64 0, i32 1
; CHECK: %[[a1:.*]] = load i8* %[[gep_a1]], align 1
; CHECK: %[[gep_b0:.*]] = getelementptr inbounds { i8, i8 }* %b, i64 0, i32 0
; CHECK: store i8 %[[a0]], i8* %[[gep_b0]], align 16
; CHECK: %[[gep_b1:.*]] = getelementptr inbounds { i8, i8 }* %b, i64 0, i32 1
; CHECK: store i8 %[[a1]], i8* %[[gep_b1]], align 1
; CHECK: ret void
entry:
%alloca = alloca { i8, i8 }, align 16
%gep_a = getelementptr { i8, i8 }* %a, i32 0, i32 0
%gep_alloca = getelementptr { i8, i8 }* %alloca, i32 0, i32 0
%gep_b = getelementptr { i8, i8 }* %b, i32 0, i32 0
store i8 420, i8* %gep_alloca, align 16
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %gep_alloca, i8* %gep_a, i32 2, i32 16, i1 false)
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %gep_b, i8* %gep_alloca, i32 2, i32 16, i1 false)
ret void
}
define void @test2() {
; CHECK: @test2
; CHECK: alloca i16
; CHECK: load i8* %{{.*}}
; CHECK: store i8 42, i8* %{{.*}}
; CHECK: ret void
entry:
%a = alloca { i8, i8, i8, i8 }, align 2
%gep1 = getelementptr { i8, i8, i8, i8 }* %a, i32 0, i32 1
%cast1 = bitcast i8* %gep1 to i16*
store volatile i16 0, i16* %cast1
%gep2 = getelementptr { i8, i8, i8, i8 }* %a, i32 0, i32 2
%result = load i8* %gep2
store i8 42, i8* %gep2
ret void
}
define void @PR13920(<2 x i64>* %a, i16* %b) {
; Test that alignments on memcpy intrinsics get propagated to loads and stores.
; CHECK: @PR13920
; CHECK: load <2 x i64>* %a, align 2
; CHECK: store <2 x i64> {{.*}}, <2 x i64>* {{.*}}, align 2
; CHECK: ret void
entry:
%aa = alloca <2 x i64>, align 16
%aptr = bitcast <2 x i64>* %a to i8*
%aaptr = bitcast <2 x i64>* %aa to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %aaptr, i8* %aptr, i32 16, i32 2, i1 false)
%bptr = bitcast i16* %b to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %bptr, i8* %aaptr, i32 16, i32 2, i1 false)
ret void
}
define void @test3(i8* %x) {
; Test that when we promote an alloca to a type with lower ABI alignment, we
; provide the needed explicit alignment that code using the alloca may be
; expecting. However, also check that any offset within an alloca can in turn
; reduce the alignment.
; CHECK: @test3
; CHECK: alloca [22 x i8], align 8
; CHECK: alloca [18 x i8], align 2
; CHECK: ret void
entry:
%a = alloca { i8*, i8*, i8* }
%b = alloca { i8*, i8*, i8* }
%a_raw = bitcast { i8*, i8*, i8* }* %a to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %a_raw, i8* %x, i32 22, i32 8, i1 false)
%b_raw = bitcast { i8*, i8*, i8* }* %b to i8*
%b_gep = getelementptr i8* %b_raw, i32 6
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %b_gep, i8* %x, i32 18, i32 2, i1 false)
ret void
}
%struct.S = type { i8, { i64 } }
define void @test4() {
; This test case triggered very strange alignment behavior with memcpy due to
; strange splitting. Reported by Duncan.
; CHECK: @test4
entry:
%D.2113 = alloca %struct.S
%Op = alloca %struct.S
%D.2114 = alloca %struct.S
%gep1 = getelementptr inbounds %struct.S* %Op, i32 0, i32 0
store i8 0, i8* %gep1, align 8
%gep2 = getelementptr inbounds %struct.S* %Op, i32 0, i32 1, i32 0
%cast = bitcast i64* %gep2 to double*
store double 0.000000e+00, double* %cast, align 8
store i64 0, i64* %gep2, align 8
%dst1 = bitcast %struct.S* %D.2114 to i8*
%src1 = bitcast %struct.S* %Op to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst1, i8* %src1, i32 16, i32 8, i1 false)
%dst2 = bitcast %struct.S* %D.2113 to i8*
%src2 = bitcast %struct.S* %D.2114 to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst2, i8* %src2, i32 16, i32 8, i1 false)
; We get 3 memcpy calls with various reasons to shrink their alignment to 1.
; CHECK: @llvm.memcpy.p0i8.p0i8.i32(i8* %{{.*}}, i8* %{{.*}}, i32 3, i32 1, i1 false)
; CHECK: @llvm.memcpy.p0i8.p0i8.i32(i8* %{{.*}}, i8* %{{.*}}, i32 8, i32 1, i1 false)
; CHECK: @llvm.memcpy.p0i8.p0i8.i32(i8* %{{.*}}, i8* %{{.*}}, i32 11, i32 1, i1 false)
ret void
}
define void @test5() {
; Test that we preserve underaligned loads and stores when splitting.
; CHECK: @test5
; CHECK: alloca [9 x i8]
; CHECK: alloca [9 x i8]
; CHECK: store volatile double 0.0{{.*}}, double* %{{.*}}, align 1
; CHECK: load i16* %{{.*}}, align 1
; CHECK: load double* %{{.*}}, align 1
; CHECK: store volatile double %{{.*}}, double* %{{.*}}, align 1
; CHECK: load i16* %{{.*}}, align 1
; CHECK: ret void
entry:
%a = alloca [18 x i8]
%raw1 = getelementptr inbounds [18 x i8]* %a, i32 0, i32 0
%ptr1 = bitcast i8* %raw1 to double*
store volatile double 0.0, double* %ptr1, align 1
%weird_gep1 = getelementptr inbounds [18 x i8]* %a, i32 0, i32 7
%weird_cast1 = bitcast i8* %weird_gep1 to i16*
%weird_load1 = load i16* %weird_cast1, align 1
%raw2 = getelementptr inbounds [18 x i8]* %a, i32 0, i32 9
%ptr2 = bitcast i8* %raw2 to double*
%d1 = load double* %ptr1, align 1
store volatile double %d1, double* %ptr2, align 1
%weird_gep2 = getelementptr inbounds [18 x i8]* %a, i32 0, i32 16
%weird_cast2 = bitcast i8* %weird_gep2 to i16*
%weird_load2 = load i16* %weird_cast2, align 1
ret void
}
define void @test6() {
; Test that we promote alignment when the underlying alloca switches to one
; that innately provides it.
; CHECK: @test6
; CHECK: alloca double
; CHECK: alloca double
; CHECK-NOT: align
; CHECK: ret void
entry:
%a = alloca [16 x i8]
%raw1 = getelementptr inbounds [16 x i8]* %a, i32 0, i32 0
%ptr1 = bitcast i8* %raw1 to double*
store volatile double 0.0, double* %ptr1, align 1
%raw2 = getelementptr inbounds [16 x i8]* %a, i32 0, i32 8
%ptr2 = bitcast i8* %raw2 to double*
%val = load double* %ptr1, align 1
store volatile double %val, double* %ptr2, align 1
ret void
}
define void @test7(i8* %out) {
; Test that we properly compute the destination alignment when rewriting
; memcpys as direct loads or stores.
; CHECK: @test7
; CHECK-NOT: alloca
entry:
%a = alloca [16 x i8]
%raw1 = getelementptr inbounds [16 x i8]* %a, i32 0, i32 0
%ptr1 = bitcast i8* %raw1 to double*
%raw2 = getelementptr inbounds [16 x i8]* %a, i32 0, i32 8
%ptr2 = bitcast i8* %raw2 to double*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %raw1, i8* %out, i32 16, i32 0, i1 false)
; CHECK: %[[val2:.*]] = load double* %{{.*}}, align 1
; CHECK: %[[val1:.*]] = load double* %{{.*}}, align 1
%val1 = load double* %ptr2, align 1
%val2 = load double* %ptr1, align 1
store double %val1, double* %ptr1, align 1
store double %val2, double* %ptr2, align 1
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %out, i8* %raw1, i32 16, i32 0, i1 false)
; CHECK: store double %[[val1]], double* %{{.*}}, align 1
; CHECK: store double %[[val2]], double* %{{.*}}, align 1
ret void
; CHECK: ret void
}