llvm/test/CodeGen/X86/stack-align.ll
Charles Davis c15a907754 [CodeGen] Don't assume that fixed stack objects are aligned in a stack-realigned function.
Summary:
After we make the adjustment, we can assume that for local allocas, but
not for stack parameters, the return address, or any other fixed stack
object (which has a negative offset and therefore lies prior to the
adjusted SP).

Fixes PR26662.

Reviewers: hfinkel, qcolombet, rnk

Subscribers: rnk, llvm-commits

Differential Revision: http://reviews.llvm.org/D18471

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265886 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-09 23:34:42 +00:00

92 lines
3.2 KiB
LLVM

; RUN: llc < %s -relocation-model=static -mcpu=yonah | FileCheck %s
; The double argument is at 4(esp) which is 16-byte aligned, but we
; are required to read in extra bytes of memory in order to fold the
; load. Bad Things may happen when reading/processing undefined bytes,
; so don't fold the load.
; PR22371 / http://reviews.llvm.org/D7474
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i686-apple-darwin8"
@G = external global double
define void @test({ double, double }* byval %z, double* %P) nounwind {
entry:
%tmp3 = load double, double* @G, align 16 ; <double> [#uses=1]
%tmp4 = tail call double @fabs( double %tmp3 ) readnone ; <double> [#uses=1]
store volatile double %tmp4, double* %P
%tmp = getelementptr { double, double }, { double, double }* %z, i32 0, i32 0 ; <double*> [#uses=1]
%tmp1 = load volatile double, double* %tmp, align 8 ; <double> [#uses=1]
%tmp2 = tail call double @fabs( double %tmp1 ) readnone ; <double> [#uses=1]
%tmp6 = fadd double %tmp4, %tmp2 ; <double> [#uses=1]
store volatile double %tmp6, double* %P, align 8
ret void
; CHECK-LABEL: test:
; CHECK: movsd {{.*}}G, %xmm{{.*}}
; CHECK: andpd %xmm{{.*}}, %xmm{{.*}}
; CHECK: movsd 4(%esp), %xmm{{.*}}
; CHECK: andpd %xmm{{.*}}, %xmm{{.*}}
}
define void @test2() alignstack(16) nounwind {
entry:
; CHECK-LABEL: test2:
; CHECK: andl{{.*}}$-16, %esp
ret void
}
; Use a call to force a spill.
define <2 x double> @test3(<2 x double> %x, <2 x double> %y) alignstack(32) nounwind {
entry:
; CHECK-LABEL: test3:
; CHECK: andl{{.*}}$-32, %esp
call void @test2()
%A = fmul <2 x double> %x, %y
ret <2 x double> %A
}
declare double @fabs(double)
; The pointer is already known aligned, so and x,-16 is eliminable.
define i32 @test4() nounwind {
entry:
%buffer = alloca [2048 x i8], align 16
%0 = ptrtoint [2048 x i8]* %buffer to i32
%and = and i32 %0, -16
ret i32 %and
; CHECK-LABEL: test4:
; CHECK-NOT: and
; CHECK: ret
}
%struct.sixteen = type { [16 x i8] }
; Accessing stack parameters shouldn't assume stack alignment. Here we should
; emit two 8-byte loads, followed by two 8-byte stores.
define x86_stdcallcc void @test5(%struct.sixteen* byval nocapture readonly align 4 %s) #0 {
%d.sroa.0 = alloca [16 x i8], align 1
%1 = getelementptr inbounds [16 x i8], [16 x i8]* %d.sroa.0, i32 0, i32 0
call void @llvm.lifetime.start(i64 16, i8* %1)
%2 = getelementptr inbounds %struct.sixteen, %struct.sixteen* %s, i32 0, i32 0, i32 0
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %1, i8* %2, i32 16, i32 1, i1 true)
call void @llvm.lifetime.end(i64 16, i8* %1)
ret void
; CHECK-LABEL: test5:
; CHECK: and
; CHECK: movsd
; CHECK-NEXT: movsd
; CHECK-NEXT: movsd
; CHECK-NEXT: movsd
}
declare void @llvm.lifetime.start(i64, i8* nocapture) argmemonly nounwind
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture readonly, i32, i32, i1) argmemonly nounwind
declare void @llvm.lifetime.end(i64, i8* nocapture) argmemonly nounwind
attributes #0 = { nounwind alignstack=16 "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" }