llvm-project/llvm/test/Transforms/SpeculateAroundPHIs/basic-x86.ll

596 lines
16 KiB
LLVM

; Test the basic functionality of speculating around PHI nodes based on reduced
; cost of the constant operands to the PHI nodes using the x86 cost model.
;
; REQUIRES: x86-registered-target
; RUN: opt -S -passes=spec-phis < %s | FileCheck %s
target triple = "x86_64-unknown-unknown"
define i32 @test_basic(i1 %flag, i32 %arg) {
; CHECK-LABEL: define i32 @test_basic(
entry:
br i1 %flag, label %a, label %b
; CHECK: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %arg, 7
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[SUM_B:.*]] = add i32 %arg, 11
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%sum = add i32 %arg, %p
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_A]], %a ], [ %[[SUM_B]], %b ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
; Check that we handle commuted operands and get the constant onto the RHS.
define i32 @test_commuted(i1 %flag, i32 %arg) {
; CHECK-LABEL: define i32 @test_commuted(
entry:
br i1 %flag, label %a, label %b
; CHECK: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %arg, 7
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[SUM_B:.*]] = add i32 %arg, 11
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%sum = add i32 %p, %arg
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_A]], %a ], [ %[[SUM_B]], %b ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
define i32 @test_split_crit_edge(i1 %flag, i32 %arg) {
; CHECK-LABEL: define i32 @test_split_crit_edge(
entry:
br i1 %flag, label %exit, label %a
; CHECK: entry:
; CHECK-NEXT: br i1 %flag, label %[[ENTRY_SPLIT:.*]], label %a
;
; CHECK: [[ENTRY_SPLIT]]:
; CHECK-NEXT: %[[SUM_ENTRY_SPLIT:.*]] = add i32 %arg, 7
; CHECK-NEXT: br label %exit
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %arg, 11
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %entry ], [ 11, %a ]
%sum = add i32 %arg, %p
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_ENTRY_SPLIT]], %[[ENTRY_SPLIT]] ], [ %[[SUM_A]], %a ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
define i32 @test_no_spec_dominating_inst(i1 %flag, i32* %ptr) {
; CHECK-LABEL: define i32 @test_no_spec_dominating_inst(
entry:
%load = load i32, i32* %ptr
br i1 %flag, label %a, label %b
; CHECK: %[[LOAD:.*]] = load i32, i32* %ptr
; CHECK-NEXT: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %[[LOAD]], 7
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[SUM_B:.*]] = add i32 %[[LOAD]], 11
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%sum = add i32 %load, %p
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_A]], %a ], [ %[[SUM_B]], %b ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
; We have special logic handling PHI nodes, make sure it doesn't get confused
; by a dominating PHI.
define i32 @test_no_spec_dominating_phi(i1 %flag1, i1 %flag2, i32 %x, i32 %y) {
; CHECK-LABEL: define i32 @test_no_spec_dominating_phi(
entry:
br i1 %flag1, label %x.block, label %y.block
; CHECK: entry:
; CHECK-NEXT: br i1 %flag1, label %x.block, label %y.block
x.block:
br label %merge
; CHECK: x.block:
; CHECK-NEXT: br label %merge
y.block:
br label %merge
; CHECK: y.block:
; CHECK-NEXT: br label %merge
merge:
%xy.phi = phi i32 [ %x, %x.block ], [ %y, %y.block ]
br i1 %flag2, label %a, label %b
; CHECK: merge:
; CHECK-NEXT: %[[XY_PHI:.*]] = phi i32 [ %x, %x.block ], [ %y, %y.block ]
; CHECK-NEXT: br i1 %flag2, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %[[XY_PHI]], 7
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[SUM_B:.*]] = add i32 %[[XY_PHI]], 11
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%sum = add i32 %xy.phi, %p
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[SUM_PHI:.*]] = phi i32 [ %[[SUM_A]], %a ], [ %[[SUM_B]], %b ]
; CHECK-NEXT: ret i32 %[[SUM_PHI]]
}
; Ensure that we will speculate some number of "free" instructions on the given
; architecture even though they are unrelated to the PHI itself.
define i32 @test_speculate_free_insts(i1 %flag, i64 %arg) {
; CHECK-LABEL: define i32 @test_speculate_free_insts(
entry:
br i1 %flag, label %a, label %b
; CHECK: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[T1_A:.*]] = trunc i64 %arg to i48
; CHECK-NEXT: %[[T2_A:.*]] = trunc i48 %[[T1_A]] to i32
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %[[T2_A]], 7
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[T1_B:.*]] = trunc i64 %arg to i48
; CHECK-NEXT: %[[T2_B:.*]] = trunc i48 %[[T1_B]] to i32
; CHECK-NEXT: %[[SUM_B:.*]] = add i32 %[[T2_B]], 11
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%t1 = trunc i64 %arg to i48
%t2 = trunc i48 %t1 to i32
%sum = add i32 %t2, %p
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_A]], %a ], [ %[[SUM_B]], %b ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
define i32 @test_speculate_free_phis(i1 %flag, i32 %arg1, i32 %arg2) {
; CHECK-LABEL: define i32 @test_speculate_free_phis(
entry:
br i1 %flag, label %a, label %b
; CHECK: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %arg1, 7
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[SUM_B:.*]] = add i32 %arg2, 11
; CHECK-NEXT: br label %exit
exit:
%p1 = phi i32 [ 7, %a ], [ 11, %b ]
%p2 = phi i32 [ %arg1, %a ], [ %arg2, %b ]
%sum = add i32 %p2, %p1
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_A]], %a ], [ %[[SUM_B]], %b ]
; We don't DCE the now unused PHI node...
; CHECK-NEXT: %{{.*}} = phi i32 [ %arg1, %a ], [ %arg2, %b ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
; We shouldn't speculate multiple uses even if each individually looks
; profitable because of the total cost.
define i32 @test_no_spec_multi_uses(i1 %flag, i32 %arg1, i32 %arg2, i32 %arg3) {
; CHECK-LABEL: define i32 @test_no_spec_multi_uses(
entry:
br i1 %flag, label %a, label %b
; CHECK: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%add1 = add i32 %arg1, %p
%add2 = add i32 %arg2, %p
%add3 = add i32 %arg3, %p
%sum1 = add i32 %add1, %add2
%sum2 = add i32 %sum1, %add3
ret i32 %sum2
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ 7, %a ], [ 11, %b ]
; CHECK-NEXT: %[[ADD1:.*]] = add i32 %arg1, %[[PHI]]
; CHECK-NEXT: %[[ADD2:.*]] = add i32 %arg2, %[[PHI]]
; CHECK-NEXT: %[[ADD3:.*]] = add i32 %arg3, %[[PHI]]
; CHECK-NEXT: %[[SUM1:.*]] = add i32 %[[ADD1]], %[[ADD2]]
; CHECK-NEXT: %[[SUM2:.*]] = add i32 %[[SUM1]], %[[ADD3]]
; CHECK-NEXT: ret i32 %[[SUM2]]
}
define i32 @test_multi_phis1(i1 %flag, i32 %arg) {
; CHECK-LABEL: define i32 @test_multi_phis1(
entry:
br i1 %flag, label %a, label %b
; CHECK: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A1:.*]] = add i32 %arg, 1
; CHECK-NEXT: %[[SUM_A2:.*]] = add i32 %[[SUM_A1]], 3
; CHECK-NEXT: %[[SUM_A3:.*]] = add i32 %[[SUM_A2]], 5
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[SUM_B1:.*]] = add i32 %arg, 2
; CHECK-NEXT: %[[SUM_B2:.*]] = add i32 %[[SUM_B1]], 4
; CHECK-NEXT: %[[SUM_B3:.*]] = add i32 %[[SUM_B2]], 6
; CHECK-NEXT: br label %exit
exit:
%p1 = phi i32 [ 1, %a ], [ 2, %b ]
%p2 = phi i32 [ 3, %a ], [ 4, %b ]
%p3 = phi i32 [ 5, %a ], [ 6, %b ]
%sum1 = add i32 %arg, %p1
%sum2 = add i32 %sum1, %p2
%sum3 = add i32 %sum2, %p3
ret i32 %sum3
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_A3]], %a ], [ %[[SUM_B3]], %b ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
; Check that the order of the PHIs doesn't impact the behavior.
define i32 @test_multi_phis2(i1 %flag, i32 %arg) {
; CHECK-LABEL: define i32 @test_multi_phis2(
entry:
br i1 %flag, label %a, label %b
; CHECK: br i1 %flag, label %a, label %b
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: %[[SUM_A1:.*]] = add i32 %arg, 1
; CHECK-NEXT: %[[SUM_A2:.*]] = add i32 %[[SUM_A1]], 3
; CHECK-NEXT: %[[SUM_A3:.*]] = add i32 %[[SUM_A2]], 5
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: %[[SUM_B1:.*]] = add i32 %arg, 2
; CHECK-NEXT: %[[SUM_B2:.*]] = add i32 %[[SUM_B1]], 4
; CHECK-NEXT: %[[SUM_B3:.*]] = add i32 %[[SUM_B2]], 6
; CHECK-NEXT: br label %exit
exit:
%p3 = phi i32 [ 5, %a ], [ 6, %b ]
%p2 = phi i32 [ 3, %a ], [ 4, %b ]
%p1 = phi i32 [ 1, %a ], [ 2, %b ]
%sum1 = add i32 %arg, %p1
%sum2 = add i32 %sum1, %p2
%sum3 = add i32 %sum2, %p3
ret i32 %sum3
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ %[[SUM_A3]], %a ], [ %[[SUM_B3]], %b ]
; CHECK-NEXT: ret i32 %[[PHI]]
}
define i32 @test_no_spec_indirectbr(i1 %flag, i32 %arg) {
; CHECK-LABEL: define i32 @test_no_spec_indirectbr(
entry:
br i1 %flag, label %a, label %b
; CHECK: entry:
; CHECK-NEXT: br i1 %flag, label %a, label %b
a:
indirectbr i8* undef, [label %exit]
; CHECK: a:
; CHECK-NEXT: indirectbr i8* undef, [label %exit]
b:
indirectbr i8* undef, [label %exit]
; CHECK: b:
; CHECK-NEXT: indirectbr i8* undef, [label %exit]
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%sum = add i32 %arg, %p
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ 7, %a ], [ 11, %b ]
; CHECK-NEXT: %[[SUM:.*]] = add i32 %arg, %[[PHI]]
; CHECK-NEXT: ret i32 %[[SUM]]
}
declare void @g()
declare i32 @__gxx_personality_v0(...)
; FIXME: We should be able to handle this case -- only the exceptional edge is
; impossible to split.
define i32 @test_no_spec_invoke_continue(i1 %flag, i32 %arg) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
; CHECK-LABEL: define i32 @test_no_spec_invoke_continue(
entry:
br i1 %flag, label %a, label %b
; CHECK: entry:
; CHECK-NEXT: br i1 %flag, label %a, label %b
a:
invoke void @g()
to label %exit unwind label %lpad
; CHECK: a:
; CHECK-NEXT: invoke void @g()
; CHECK-NEXT: to label %exit unwind label %lpad
b:
invoke void @g()
to label %exit unwind label %lpad
; CHECK: b:
; CHECK-NEXT: invoke void @g()
; CHECK-NEXT: to label %exit unwind label %lpad
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%sum = add i32 %arg, %p
ret i32 %sum
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ 7, %a ], [ 11, %b ]
; CHECK-NEXT: %[[SUM:.*]] = add i32 %arg, %[[PHI]]
; CHECK-NEXT: ret i32 %[[SUM]]
lpad:
%lp = landingpad { i8*, i32 }
cleanup
resume { i8*, i32 } undef
}
define i32 @test_no_spec_landingpad(i32 %arg, i32* %ptr) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
; CHECK-LABEL: define i32 @test_no_spec_landingpad(
entry:
invoke void @g()
to label %invoke.cont unwind label %lpad
; CHECK: entry:
; CHECK-NEXT: invoke void @g()
; CHECK-NEXT: to label %invoke.cont unwind label %lpad
invoke.cont:
invoke void @g()
to label %exit unwind label %lpad
; CHECK: invoke.cont:
; CHECK-NEXT: invoke void @g()
; CHECK-NEXT: to label %exit unwind label %lpad
lpad:
%p = phi i32 [ 7, %entry ], [ 11, %invoke.cont ]
%lp = landingpad { i8*, i32 }
cleanup
%sum = add i32 %arg, %p
store i32 %sum, i32* %ptr
resume { i8*, i32 } undef
; CHECK: lpad:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ 7, %entry ], [ 11, %invoke.cont ]
exit:
ret i32 0
}
declare i32 @__CxxFrameHandler3(...)
define i32 @test_no_spec_cleanuppad(i32 %arg, i32* %ptr) personality i32 (...)* @__CxxFrameHandler3 {
; CHECK-LABEL: define i32 @test_no_spec_cleanuppad(
entry:
invoke void @g()
to label %invoke.cont unwind label %lpad
; CHECK: entry:
; CHECK-NEXT: invoke void @g()
; CHECK-NEXT: to label %invoke.cont unwind label %lpad
invoke.cont:
invoke void @g()
to label %exit unwind label %lpad
; CHECK: invoke.cont:
; CHECK-NEXT: invoke void @g()
; CHECK-NEXT: to label %exit unwind label %lpad
lpad:
%p = phi i32 [ 7, %entry ], [ 11, %invoke.cont ]
%cp = cleanuppad within none []
%sum = add i32 %arg, %p
store i32 %sum, i32* %ptr
cleanupret from %cp unwind to caller
; CHECK: lpad:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ 7, %entry ], [ 11, %invoke.cont ]
exit:
ret i32 0
}
; Check that we don't fall over when confronted with seemingly reasonable code
; for us to handle but in an unreachable region and with non-PHI use-def
; cycles.
define i32 @test_unreachable_non_phi_cycles(i1 %flag, i32 %arg) {
; CHECK-LABEL: define i32 @test_unreachable_non_phi_cycles(
entry:
ret i32 42
; CHECK: entry:
; CHECK-NEXT: ret i32 42
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: br label %exit
exit:
%p = phi i32 [ 7, %a ], [ 11, %b ]
%zext = zext i32 %sum to i64
%trunc = trunc i64 %zext to i32
%sum = add i32 %trunc, %p
br i1 %flag, label %a, label %b
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i32 [ 7, %a ], [ 11, %b ]
; CHECK-NEXT: %[[ZEXT:.*]] = zext i32 %[[SUM:.*]] to i64
; CHECK-NEXT: %[[TRUNC:.*]] = trunc i64 %[[ZEXT]] to i32
; CHECK-NEXT: %[[SUM]] = add i32 %[[TRUNC]], %[[PHI]]
; CHECK-NEXT: br i1 %flag, label %a, label %b
}
; Check that we don't speculate in the face of an expensive immediate. There
; are two reasons this should never speculate. First, even a local analysis
; should fail because it makes some paths (%a) potentially more expensive due
; to multiple uses of the immediate. Additionally, when we go to speculate the
; instructions, their cost will also be too high.
; FIXME: The goal is really to test the first property, but there doesn't
; happen to be any way to use free-to-speculate instructions here so that it
; would be the only interesting property.
define i64 @test_expensive_imm(i32 %flag, i64 %arg) {
; CHECK-LABEL: define i64 @test_expensive_imm(
entry:
switch i32 %flag, label %a [
i32 1, label %b
i32 2, label %c
i32 3, label %d
]
; CHECK: switch i32 %flag, label %a [
; CHECK-NEXT: i32 1, label %b
; CHECK-NEXT: i32 2, label %c
; CHECK-NEXT: i32 3, label %d
; CHECK-NEXT: ]
a:
br label %exit
; CHECK: a:
; CHECK-NEXT: br label %exit
b:
br label %exit
; CHECK: b:
; CHECK-NEXT: br label %exit
c:
br label %exit
; CHECK: c:
; CHECK-NEXT: br label %exit
d:
br label %exit
; CHECK: d:
; CHECK-NEXT: br label %exit
exit:
%p = phi i64 [ 4294967296, %a ], [ 1, %b ], [ 1, %c ], [ 1, %d ]
%sum1 = add i64 %arg, %p
%sum2 = add i64 %sum1, %p
ret i64 %sum2
; CHECK: exit:
; CHECK-NEXT: %[[PHI:.*]] = phi i64 [ {{[0-9]+}}, %a ], [ 1, %b ], [ 1, %c ], [ 1, %d ]
; CHECK-NEXT: %[[SUM1:.*]] = add i64 %arg, %[[PHI]]
; CHECK-NEXT: %[[SUM2:.*]] = add i64 %[[SUM1]], %[[PHI]]
; CHECK-NEXT: ret i64 %[[SUM2]]
}
define i32 @test_no_spec_non_postdominating_uses(i1 %flag1, i1 %flag2, i32 %arg) {
; CHECK-LABEL: define i32 @test_no_spec_non_postdominating_uses(
entry:
br i1 %flag1, label %a, label %b
; CHECK: br i1 %flag1, label %a, label %b
a:
br label %merge
; CHECK: a:
; CHECK-NEXT: %[[SUM_A:.*]] = add i32 %arg, 7
; CHECK-NEXT: br label %merge
b:
br label %merge
; CHECK: b:
; CHECK-NEXT: %[[SUM_B:.*]] = add i32 %arg, 11
; CHECK-NEXT: br label %merge
merge:
%p1 = phi i32 [ 7, %a ], [ 11, %b ]
%p2 = phi i32 [ 13, %a ], [ 42, %b ]
%sum1 = add i32 %arg, %p1
br i1 %flag2, label %exit1, label %exit2
; CHECK: merge:
; CHECK-NEXT: %[[PHI1:.*]] = phi i32 [ %[[SUM_A]], %a ], [ %[[SUM_B]], %b ]
; CHECK-NEXT: %[[PHI2:.*]] = phi i32 [ 13, %a ], [ 42, %b ]
; CHECK-NEXT: br i1 %flag2, label %exit1, label %exit2
exit1:
ret i32 %sum1
; CHECK: exit1:
; CHECK-NEXT: ret i32 %[[PHI1]]
exit2:
%sum2 = add i32 %arg, %p2
ret i32 %sum2
; CHECK: exit2:
; CHECK-NEXT: %[[SUM2:.*]] = add i32 %arg, %[[PHI2]]
; CHECK-NEXT: ret i32 %[[SUM2]]
}