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llvm-mirror/test/Transforms/EarlyCSE/guards.ll

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[EarlyCSE] Simplify guard intrinsics Summary: This change teaches EarlyCSE some basic properties of guard intrinsics: - Guard intrinsics read all memory, but don't write to any memory - After a guard has executed, the condition it was guarding on can be assumed to be true - Guard intrinsics on a constant `true` are no-ops Reviewers: reames, hfinkel Subscribers: mcrosier, llvm-commits Differential Revision: http://reviews.llvm.org/D19578 llvm-svn: 268120
2016-04-29 23:52:58 +02:00
; RUN: opt -S -early-cse < %s | FileCheck %s
[EarlyCSE] Optionally use MemorySSA. NFC. Summary: Use MemorySSA, if requested, to do less conservative memory dependency checking. This change doesn't enable the MemorySSA enhanced EarlyCSE in the default pipelines, so should be NFC. Reviewers: dberlin, sanjoy, reames, majnemer Subscribers: mcrosier, llvm-commits Differential Revision: http://reviews.llvm.org/D19821 llvm-svn: 280279
2016-08-31 21:24:10 +02:00
; RUN: opt < %s -S -basicaa -early-cse-memssa | FileCheck %s
[EarlyCSE] Simplify guard intrinsics Summary: This change teaches EarlyCSE some basic properties of guard intrinsics: - Guard intrinsics read all memory, but don't write to any memory - After a guard has executed, the condition it was guarding on can be assumed to be true - Guard intrinsics on a constant `true` are no-ops Reviewers: reames, hfinkel Subscribers: mcrosier, llvm-commits Differential Revision: http://reviews.llvm.org/D19578 llvm-svn: 268120
2016-04-29 23:52:58 +02:00
declare void @llvm.experimental.guard(i1,...)
define i32 @test0(i32* %ptr, i1 %cond) {
; We can do store to load forwarding over a guard, since it does not
; clobber memory
; CHECK-LABEL: @test0(
; CHECK-NEXT: store i32 40, i32* %ptr
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
; CHECK-NEXT: ret i32 40
store i32 40, i32* %ptr
call void(i1,...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
%rval = load i32, i32* %ptr
ret i32 %rval
}
define i32 @test1(i32* %val, i1 %cond) {
; We can CSE loads over a guard, since it does not clobber memory
; CHECK-LABEL: @test1(
; CHECK-NEXT: %val0 = load i32, i32* %val
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
; CHECK-NEXT: ret i32 0
%val0 = load i32, i32* %val
call void(i1,...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
%val1 = load i32, i32* %val
%rval = sub i32 %val0, %val1
ret i32 %rval
}
define i32 @test2() {
; Guards on "true" get removed
; CHECK-LABEL: @test2(
; CHECK-NEXT: ret i32 0
call void(i1, ...) @llvm.experimental.guard(i1 true) [ "deopt"() ]
ret i32 0
}
define i32 @test3(i32 %val) {
; After a guard has executed the condition it was guarding is known to
; be true.
; CHECK-LABEL: @test3(
; CHECK-NEXT: %cond0 = icmp slt i32 %val, 40
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond0) [ "deopt"() ]
; CHECK-NEXT: ret i32 -1
%cond0 = icmp slt i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond0) [ "deopt"() ]
%cond1 = icmp slt i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
%cond2 = icmp slt i32 %val, 40
%rval = sext i1 %cond2 to i32
ret i32 %rval
}
define i32 @test3.unhandled(i32 %val) {
; After a guard has executed the condition it was guarding is known to
; be true.
; CHECK-LABEL: @test3.unhandled(
; CHECK-NEXT: %cond0 = icmp slt i32 %val, 40
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond0) [ "deopt"() ]
; CHECK-NEXT: %cond1 = icmp sge i32 %val, 40
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
; CHECK-NEXT: ret i32 0
; Demonstrates a case we do not yet handle (it is legal to fold %cond2
; to false)
%cond0 = icmp slt i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond0) [ "deopt"() ]
%cond1 = icmp sge i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
ret i32 0
}
define i32 @test4(i32 %val, i1 %c) {
; Same as test3, but with some control flow involved.
; CHECK-LABEL: @test4(
; CHECK: entry:
; CHECK-NEXT: %cond0 = icmp slt i32 %val, 40
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond0
; CHECK-NEXT: br label %bb0
; CHECK: bb0:
; CHECK-NEXT: %cond2 = icmp ult i32 %val, 200
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond2
; CHECK-NEXT: br i1 %c, label %left, label %right
; CHECK: left:
; CHECK-NEXT: ret i32 0
; CHECK: right:
; CHECK-NEXT: ret i32 20
entry:
%cond0 = icmp slt i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond0) [ "deopt"() ]
%cond1 = icmp slt i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
br label %bb0
bb0:
%cond2 = icmp ult i32 %val, 200
call void(i1,...) @llvm.experimental.guard(i1 %cond2) [ "deopt"() ]
br i1 %c, label %left, label %right
left:
%cond3 = icmp ult i32 %val, 200
call void(i1,...) @llvm.experimental.guard(i1 %cond3) [ "deopt"() ]
ret i32 0
right:
ret i32 20
}
define i32 @test5(i32 %val, i1 %c) {
; Same as test4, but the %left block has mutliple predecessors.
; CHECK-LABEL: @test5(
; CHECK: entry:
; CHECK-NEXT: %cond0 = icmp slt i32 %val, 40
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond0
; CHECK-NEXT: br label %bb0
; CHECK: bb0:
; CHECK-NEXT: %cond2 = icmp ult i32 %val, 200
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %cond2
; CHECK-NEXT: br i1 %c, label %left, label %right
; CHECK: left:
; CHECK-NEXT: br label %right
; CHECK: right:
; CHECK-NEXT: br label %left
entry:
%cond0 = icmp slt i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond0) [ "deopt"() ]
%cond1 = icmp slt i32 %val, 40
call void(i1,...) @llvm.experimental.guard(i1 %cond1) [ "deopt"() ]
br label %bb0
bb0:
%cond2 = icmp ult i32 %val, 200
call void(i1,...) @llvm.experimental.guard(i1 %cond2) [ "deopt"() ]
br i1 %c, label %left, label %right
left:
%cond3 = icmp ult i32 %val, 200
call void(i1,...) @llvm.experimental.guard(i1 %cond3) [ "deopt"() ]
br label %right
right:
br label %left
}
define void @test6(i1 %c, i32* %ptr) {
; Check that we do not DSE over calls to @llvm.experimental.guard.
; Guard intrinsics do _read_ memory, so th call to guard below needs
; to see the store of 500 to %ptr
; CHECK-LABEL: @test6(
; CHECK-NEXT: store i32 500, i32* %ptr
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %c) [ "deopt"() ]
; CHECK-NEXT: store i32 600, i32* %ptr
store i32 500, i32* %ptr
call void(i1,...) @llvm.experimental.guard(i1 %c) [ "deopt"() ]
store i32 600, i32* %ptr
ret void
}
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