Files
archived-llvm/test/CodeGen/WebAssembly/reg-stackify.ll
Derek Schuff 7ea47333dc [WebAssemly] Don't move calls or stores past intervening loads
The register stackifier currently checks for intervening stores (and
loads that may alias them) but doesn't account for the fact that the
instruction being moved may affect intervening loads.

Differential Revision: http://reviews.llvm.org/D17298

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261014 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-16 21:44:19 +00:00

351 lines
11 KiB
LLVM

; RUN: llc < %s -asm-verbose=false -verify-machineinstrs | FileCheck %s
; Test the register stackifier pass.
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
; No because of pointer aliasing.
; CHECK-LABEL: no0:
; CHECK: return $1{{$}}
define i32 @no0(i32* %p, i32* %q) {
%t = load i32, i32* %q
store i32 0, i32* %p
ret i32 %t
}
; No because of side effects.
; CHECK-LABEL: no1:
; CHECK: return $1{{$}}
define i32 @no1(i32* %p, i32* dereferenceable(4) %q) {
%t = load volatile i32, i32* %q, !invariant.load !0
store volatile i32 0, i32* %p
ret i32 %t
}
; Yes because of invariant load and no side effects.
; CHECK-LABEL: yes0:
; CHECK: return $pop0{{$}}
define i32 @yes0(i32* %p, i32* dereferenceable(4) %q) {
%t = load i32, i32* %q, !invariant.load !0
store i32 0, i32* %p
ret i32 %t
}
; Yes because of no intervening side effects.
; CHECK-LABEL: yes1:
; CHECK: return $pop0{{$}}
define i32 @yes1(i32* %q) {
%t = load volatile i32, i32* %q
ret i32 %t
}
; Don't schedule stack uses into the stack. To reduce register pressure, the
; scheduler might be tempted to move the definition of $2 down. However, this
; would risk getting incorrect liveness if the instructions are later
; rearranged to make the stack contiguous.
; CHECK-LABEL: stack_uses:
; CHECK-NEXT: .param i32, i32, i32, i32{{$}}
; CHECK-NEXT: .result i32{{$}}
; CHECK-NEXT: block{{$}}
; CHECK-NEXT: i32.const $push13=, 1{{$}}
; CHECK-NEXT: i32.lt_s $push0=, $0, $pop13{{$}}
; CHECK-NEXT: i32.const $push1=, 2{{$}}
; CHECK-NEXT: i32.lt_s $push2=, $1, $pop1{{$}}
; CHECK-NEXT: i32.xor $push5=, $pop0, $pop2{{$}}
; CHECK-NEXT: i32.const $push12=, 1{{$}}
; CHECK-NEXT: i32.lt_s $push3=, $2, $pop12{{$}}
; CHECK-NEXT: i32.const $push11=, 2{{$}}
; CHECK-NEXT: i32.lt_s $push4=, $3, $pop11{{$}}
; CHECK-NEXT: i32.xor $push6=, $pop3, $pop4{{$}}
; CHECK-NEXT: i32.xor $push7=, $pop5, $pop6{{$}}
; CHECK-NEXT: i32.const $push10=, 1{{$}}
; CHECK-NEXT: i32.ne $push8=, $pop7, $pop10{{$}}
; CHECK-NEXT: br_if 0, $pop8{{$}}
; CHECK-NEXT: i32.const $push9=, 0{{$}}
; CHECK-NEXT: return $pop9{{$}}
; CHECK-NEXT: .LBB4_2:
; CHECK-NEXT: end_block{{$}}
; CHECK-NEXT: i32.const $push14=, 1{{$}}
; CHECK-NEXT: return $pop14{{$}}
define i32 @stack_uses(i32 %x, i32 %y, i32 %z, i32 %w) {
entry:
%c = icmp sle i32 %x, 0
%d = icmp sle i32 %y, 1
%e = icmp sle i32 %z, 0
%f = icmp sle i32 %w, 1
%g = xor i1 %c, %d
%h = xor i1 %e, %f
%i = xor i1 %g, %h
br i1 %i, label %true, label %false
true:
ret i32 0
false:
ret i32 1
}
; Test an interesting case where the load has multiple uses and cannot
; be trivially stackified. However, it can be stackified with a tee_local.
; CHECK-LABEL: multiple_uses:
; CHECK-NEXT: .param i32, i32, i32{{$}}
; CHECK-NEXT: .local i32{{$}}
; CHECK-NEXT: block{{$}}
; CHECK-NEXT: i32.load $push[[NUM0:[0-9]+]]=, 0($2){{$}}
; CHECK-NEXT: tee_local $push[[NUM1:[0-9]+]]=, $3=, $pop[[NUM0]]{{$}}
; CHECK-NEXT: i32.ge_u $push[[NUM2:[0-9]+]]=, $pop[[NUM1]], $1{{$}}
; CHECK-NEXT: br_if 0, $pop[[NUM2]]{{$}}
; CHECK-NEXT: i32.lt_u $push[[NUM3:[0-9]+]]=, $3, $0{{$}}
; CHECK-NEXT: br_if 0, $pop[[NUM3]]{{$}}
; CHECK-NEXT: i32.store $discard=, 0($2), $3{{$}}
; CHECK-NEXT: .LBB5_3:
; CHECK-NEXT: end_block{{$}}
; CHECK-NEXT: return{{$}}
define void @multiple_uses(i32* %arg0, i32* %arg1, i32* %arg2) nounwind {
bb:
br label %loop
loop:
%tmp7 = load i32, i32* %arg2
%tmp8 = inttoptr i32 %tmp7 to i32*
%tmp9 = icmp uge i32* %tmp8, %arg1
%tmp10 = icmp ult i32* %tmp8, %arg0
%tmp11 = or i1 %tmp9, %tmp10
br i1 %tmp11, label %back, label %then
then:
store i32 %tmp7, i32* %arg2
br label %back
back:
br i1 undef, label %return, label %loop
return:
ret void
}
; Don't stackify stores effects across other instructions with side effects.
; CHECK: side_effects:
; CHECK: store
; CHECK-NEXT: call
; CHECK-NEXT: store
; CHECK-NEXT: call
declare void @evoke_side_effects()
define hidden void @stackify_store_across_side_effects(double* nocapture %d) {
entry:
store double 2.0, double* %d
call void @evoke_side_effects()
store double 2.0, double* %d
call void @evoke_side_effects()
ret void
}
; Div instructions have side effects and can't be reordered, but this entire
; function should still be able to be stackified because it's already in
; tree order.
; CHECK-LABEL: div_tree:
; CHECK-NEXT: .param i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32, i32{{$}}
; CHECK-NEXT: .result i32{{$}}
; CHECK-NEXT: i32.div_s $push0=, $0, $1
; CHECK-NEXT: i32.div_s $push1=, $2, $3
; CHECK-NEXT: i32.div_s $push2=, $pop0, $pop1
; CHECK-NEXT: i32.div_s $push3=, $4, $5
; CHECK-NEXT: i32.div_s $push4=, $6, $7
; CHECK-NEXT: i32.div_s $push5=, $pop3, $pop4
; CHECK-NEXT: i32.div_s $push6=, $pop2, $pop5
; CHECK-NEXT: i32.div_s $push7=, $8, $9
; CHECK-NEXT: i32.div_s $push8=, $10, $11
; CHECK-NEXT: i32.div_s $push9=, $pop7, $pop8
; CHECK-NEXT: i32.div_s $push10=, $12, $13
; CHECK-NEXT: i32.div_s $push11=, $14, $15
; CHECK-NEXT: i32.div_s $push12=, $pop10, $pop11
; CHECK-NEXT: i32.div_s $push13=, $pop9, $pop12
; CHECK-NEXT: i32.div_s $push14=, $pop6, $pop13
; CHECK-NEXT: return $pop14
define i32 @div_tree(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e, i32 %f, i32 %g, i32 %h, i32 %i, i32 %j, i32 %k, i32 %l, i32 %m, i32 %n, i32 %o, i32 %p) {
entry:
%div = sdiv i32 %a, %b
%div1 = sdiv i32 %c, %d
%div2 = sdiv i32 %div, %div1
%div3 = sdiv i32 %e, %f
%div4 = sdiv i32 %g, %h
%div5 = sdiv i32 %div3, %div4
%div6 = sdiv i32 %div2, %div5
%div7 = sdiv i32 %i, %j
%div8 = sdiv i32 %k, %l
%div9 = sdiv i32 %div7, %div8
%div10 = sdiv i32 %m, %n
%div11 = sdiv i32 %o, %p
%div12 = sdiv i32 %div10, %div11
%div13 = sdiv i32 %div9, %div12
%div14 = sdiv i32 %div6, %div13
ret i32 %div14
}
; A simple multiple-use case.
; CHECK-LABEL: simple_multiple_use:
; CHECK-NEXT: .param i32, i32{{$}}
; CHECK-NEXT: i32.mul $push[[NUM0:[0-9]+]]=, $1, $0{{$}}
; CHECK-NEXT: tee_local $push[[NUM1:[0-9]+]]=, $0=, $pop[[NUM0]]{{$}}
; CHECK-NEXT: call use_a@FUNCTION, $pop[[NUM1]]{{$}}
; CHECK-NEXT: call use_b@FUNCTION, $0{{$}}
; CHECK-NEXT: return{{$}}
declare void @use_a(i32)
declare void @use_b(i32)
define void @simple_multiple_use(i32 %x, i32 %y) {
%mul = mul i32 %y, %x
call void @use_a(i32 %mul)
call void @use_b(i32 %mul)
ret void
}
; Multiple uses of the same value in one instruction.
; CHECK-LABEL: multiple_uses_in_same_insn:
; CHECK-NEXT: .param i32, i32{{$}}
; CHECK-NEXT: i32.mul $push[[NUM0:[0-9]+]]=, $1, $0{{$}}
; CHECK-NEXT: tee_local $push[[NUM1:[0-9]+]]=, $0=, $pop[[NUM0]]{{$}}
; CHECK-NEXT: call use_2@FUNCTION, $pop[[NUM1]], $0{{$}}
; CHECK-NEXT: return{{$}}
declare void @use_2(i32, i32)
define void @multiple_uses_in_same_insn(i32 %x, i32 %y) {
%mul = mul i32 %y, %x
call void @use_2(i32 %mul, i32 %mul)
ret void
}
; Commute operands to achieve better stackifying.
; CHECK-LABEL: commute:
; CHECK-NEXT: .result i32{{$}}
; CHECK-NEXT: i32.call $push0=, red@FUNCTION{{$}}
; CHECK-NEXT: i32.call $push1=, green@FUNCTION{{$}}
; CHECK-NEXT: i32.add $push2=, $pop0, $pop1{{$}}
; CHECK-NEXT: i32.call $push3=, blue@FUNCTION{{$}}
; CHECK-NEXT: i32.add $push4=, $pop2, $pop3{{$}}
; CHECK-NEXT: return $pop4{{$}}
declare i32 @red()
declare i32 @green()
declare i32 @blue()
define i32 @commute() {
%call = call i32 @red()
%call1 = call i32 @green()
%add = add i32 %call1, %call
%call2 = call i32 @blue()
%add3 = add i32 %add, %call2
ret i32 %add3
}
; Don't stackify a register when it would move a the def of the register past
; an implicit get_local for the register.
; CHECK-LABEL: no_stackify_past_use:
; CHECK: i32.call $1=, callee@FUNCTION, $0
; CHECK: i32.const $push0=, 1
; CHECK: i32.add $push1=, $0, $pop0
; CHECK: i32.call $push2=, callee@FUNCTION, $pop1
; CHECK: i32.add $push3=, $1, $pop2
; CHECK: i32.mul $push4=, $1, $pop3
; CHECK: return $pop4
declare i32 @callee(i32)
define i32 @no_stackify_past_use(i32 %arg) {
%tmp1 = call i32 @callee(i32 %arg)
%tmp2 = add i32 %arg, 1
%tmp3 = call i32 @callee(i32 %tmp2)
%tmp5 = add i32 %tmp3, %tmp1
%tmp6 = mul i32 %tmp5, %tmp1
ret i32 %tmp6
}
; Stackify individual defs of virtual registers with multiple defs.
; CHECK-LABEL: multiple_defs:
; CHECK: f64.add $push[[NUM0:[0-9]+]]=, ${{[0-9]+}}, $pop{{[0-9]+}}{{$}}
; CHECK-NEXT: tee_local $push[[NUM1:[0-9]+]]=, $[[NUM2:[0-9]+]]=, $pop[[NUM0]]{{$}}
; CHECK-NEXT: f64.select $push{{[0-9]+}}=, $pop{{[0-9]+}}, $pop[[NUM1]], ${{[0-9]+}}{{$}}
; CHECK: $[[NUM2]]=,
; CHECK: $[[NUM2]]=,
define void @multiple_defs(i32 %arg, i32 %arg1, i1 %arg2, i1 %arg3, i1 %arg4) {
bb:
br label %bb5
bb5: ; preds = %bb21, %bb
%tmp = phi double [ 0.000000e+00, %bb ], [ %tmp22, %bb21 ]
%tmp6 = phi double [ 0.000000e+00, %bb ], [ %tmp23, %bb21 ]
%tmp7 = fcmp olt double %tmp6, 2.323450e+01
br i1 %tmp7, label %bb8, label %bb21
bb8: ; preds = %bb17, %bb5
%tmp9 = phi double [ %tmp19, %bb17 ], [ %tmp, %bb5 ]
%tmp10 = fadd double %tmp6, -1.000000e+00
%tmp11 = select i1 %arg2, double -1.135357e+04, double %tmp10
%tmp12 = fadd double %tmp11, %tmp9
br i1 %arg3, label %bb17, label %bb13
bb13: ; preds = %bb8
%tmp14 = or i32 %arg1, 2
%tmp15 = icmp eq i32 %tmp14, 14
%tmp16 = select i1 %tmp15, double -1.135357e+04, double 0xBFCE147AE147B000
br label %bb17
bb17: ; preds = %bb13, %bb8
%tmp18 = phi double [ %tmp16, %bb13 ], [ %tmp10, %bb8 ]
%tmp19 = fadd double %tmp18, %tmp12
%tmp20 = fcmp olt double %tmp6, 2.323450e+01
br i1 %tmp20, label %bb8, label %bb21
bb21: ; preds = %bb17, %bb5
%tmp22 = phi double [ %tmp, %bb5 ], [ %tmp9, %bb17 ]
%tmp23 = fadd double %tmp6, 1.000000e+00
br label %bb5
}
; Don't move calls past loads
; CHECK-LABEL: no_stackify_call_past_load:
; CHECK: i32.call $0=, red
; CHECK: i32.const $push0=, 0
; CHECK: i32.load $1=, count($pop0)
@count = hidden global i32 0, align 4
define i32 @no_stackify_call_past_load() {
%a = call i32 @red()
%b = load i32, i32* @count, align 4
call i32 @callee(i32 %a)
ret i32 %b
; use of a
}
; Don't move stores past loads if there may be aliasing
; CHECK-LABEL: no_stackify_store_past_load
; CHECK: i32.store {{.*}}, 0($1), $0
; CHECK: i32.load {{.*}}, 0($2)
; CHECK: i32.call {{.*}}, callee@FUNCTION, $0
define i32 @no_stackify_store_past_load(i32 %a, i32* %p1, i32* %p2) {
store i32 %a, i32* %p1
%b = load i32, i32* %p2, align 4
call i32 @callee(i32 %a)
ret i32 %b
}
; Can still stackify past invariant loads.
; CHECK-LABEL: store_past_invar_load
; CHECK: i32.store $push{{.*}}, 0($1), $0
; CHECK: i32.call {{.*}}, callee@FUNCTION, $pop
; CHECK: i32.load $push{{.*}}, 0($2)
; CHECK: return $pop
define i32 @store_past_invar_load(i32 %a, i32* %p1, i32* dereferenceable(4) %p2) {
store i32 %a, i32* %p1
%b = load i32, i32* %p2, !invariant.load !0
call i32 @callee(i32 %a)
ret i32 %b
}
!0 = !{}