mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-24 13:33:37 +02:00
812a2fc1c7
Summary:
This patch allows JumpThreading also thread through guards.
Virtually, guard(cond) is equivalent to the following construction:
if (cond) { do something } else {deoptimize}
Yet it is not explicitly converted into IFs before lowering.
This patch enables early threading through guards in simple cases.
Currently it covers the following situation:
if (cond1) {
// code A
} else {
// code B
}
// code C
guard(cond2)
// code D
If there is implication cond1 => cond2 or !cond1 => cond2, we can transform
this construction into the following:
if (cond1) {
// code A
// code C
} else {
// code B
// code C
guard(cond2)
}
// code D
Thus, removing the guard from one of execution branches.
Patch by Max Kazantsev!
Reviewers: reames, apilipenko, igor-laevsky, anna, sanjoy
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D29620
llvm-svn: 294617
133 lines
3.5 KiB
LLVM
133 lines
3.5 KiB
LLVM
; RUN: opt < %s -jump-threading -dce -S | FileCheck %s
|
|
|
|
declare void @llvm.experimental.guard(i1, ...)
|
|
|
|
declare i32 @f1()
|
|
declare i32 @f2()
|
|
|
|
define i32 @branch_implies_guard(i32 %a) {
|
|
; CHECK-LABEL: @branch_implies_guard(
|
|
%cond = icmp slt i32 %a, 10
|
|
br i1 %cond, label %T1, label %F1
|
|
|
|
T1:
|
|
; CHECK: T1.split
|
|
; CHECK: %v1 = call i32 @f1()
|
|
; CHECK-NEXT: %retVal
|
|
; CHECK-NEXT: br label %Merge
|
|
%v1 = call i32 @f1()
|
|
br label %Merge
|
|
|
|
F1:
|
|
; CHECK: F1.split
|
|
; CHECK: %v2 = call i32 @f2()
|
|
; CHECK-NEXT: %retVal
|
|
; CHECK-NEXT: %condGuard
|
|
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard
|
|
; CHECK-NEXT: br label %Merge
|
|
%v2 = call i32 @f2()
|
|
br label %Merge
|
|
|
|
Merge:
|
|
; CHECK: Merge
|
|
; CHECK-NOT: call void(i1, ...) @llvm.experimental.guard(
|
|
%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
|
|
%retVal = add i32 %retPhi, 10
|
|
%condGuard = icmp slt i32 %a, 20
|
|
call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
|
|
ret i32 %retVal
|
|
}
|
|
|
|
define i32 @not_branch_implies_guard(i32 %a) {
|
|
; CHECK-LABEL: @not_branch_implies_guard(
|
|
%cond = icmp slt i32 %a, 20
|
|
br i1 %cond, label %T1, label %F1
|
|
|
|
T1:
|
|
; CHECK: T1.split:
|
|
; CHECK-NEXT: %v1 = call i32 @f1()
|
|
; CHECK-NEXT: %retVal
|
|
; CHECK-NEXT: %condGuard
|
|
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard
|
|
; CHECK-NEXT: br label %Merge
|
|
%v1 = call i32 @f1()
|
|
br label %Merge
|
|
|
|
F1:
|
|
; CHECK: F1.split:
|
|
; CHECK-NEXT: %v2 = call i32 @f2()
|
|
; CHECK-NEXT: %retVal
|
|
; CHECK-NEXT: br label %Merge
|
|
%v2 = call i32 @f2()
|
|
br label %Merge
|
|
|
|
Merge:
|
|
; CHECK: Merge
|
|
; CHECK-NOT: call void(i1, ...) @llvm.experimental.guard(
|
|
%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
|
|
%retVal = add i32 %retPhi, 10
|
|
%condGuard = icmp sgt i32 %a, 10
|
|
call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
|
|
ret i32 %retVal
|
|
}
|
|
|
|
define i32 @branch_overlaps_guard(i32 %a) {
|
|
; CHECK-LABEL: @branch_overlaps_guard(
|
|
%cond = icmp slt i32 %a, 20
|
|
br i1 %cond, label %T1, label %F1
|
|
|
|
T1:
|
|
; CHECK: T1:
|
|
; CHECK-NEXT: %v1 = call i32 @f1()
|
|
; CHECK-NEXT: br label %Merge
|
|
%v1 = call i32 @f1()
|
|
br label %Merge
|
|
|
|
F1:
|
|
; CHECK: F1:
|
|
; CHECK-NEXT: %v2 = call i32 @f2()
|
|
; CHECK-NEXT: br label %Merge
|
|
%v2 = call i32 @f2()
|
|
br label %Merge
|
|
|
|
Merge:
|
|
; CHECK: Merge
|
|
; CHECK: %condGuard = icmp slt i32 %a, 10
|
|
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
|
|
%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
|
|
%retVal = add i32 %retPhi, 10
|
|
%condGuard = icmp slt i32 %a, 10
|
|
call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
|
|
ret i32 %retVal
|
|
}
|
|
|
|
define i32 @branch_doesnt_overlap_guard(i32 %a) {
|
|
; CHECK-LABEL: @branch_doesnt_overlap_guard(
|
|
%cond = icmp slt i32 %a, 10
|
|
br i1 %cond, label %T1, label %F1
|
|
|
|
T1:
|
|
; CHECK: T1:
|
|
; CHECK-NEXT: %v1 = call i32 @f1()
|
|
; CHECK-NEXT: br label %Merge
|
|
%v1 = call i32 @f1()
|
|
br label %Merge
|
|
|
|
F1:
|
|
; CHECK: F1:
|
|
; CHECK-NEXT: %v2 = call i32 @f2()
|
|
; CHECK-NEXT: br label %Merge
|
|
%v2 = call i32 @f2()
|
|
br label %Merge
|
|
|
|
Merge:
|
|
; CHECK: Merge
|
|
; CHECK: %condGuard = icmp sgt i32 %a, 20
|
|
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %condGuard) [ "deopt"() ]
|
|
%retPhi = phi i32 [ %v1, %T1 ], [ %v2, %F1 ]
|
|
%retVal = add i32 %retPhi, 10
|
|
%condGuard = icmp sgt i32 %a, 20
|
|
call void(i1, ...) @llvm.experimental.guard( i1 %condGuard )[ "deopt"() ]
|
|
ret i32 %retVal
|
|
}
|