llvm-project/llvm/test/CodeGen/PowerPC/cmp_elimination.ll
Fangrui Song 398d68f624 [PPCMIPeephole] Fix incorrect compare elimination
D38236 moves a redundant compare instruction from the loop body to the
preheader.

It has a bug: when `MBB1 == &MBB2`, there may be only one compare instruction in the
loop. The code will lift the compare instruction to the preheader, failing to
account for the change of the compare result in a tail call, leading to a miscompile.

Suppress the compare elimination to fix https://github.com/llvm/llvm-project/issues/62294

Reviewed By: #powerpc, nemanjai

Differential Revision: https://reviews.llvm.org/D149030
2023-04-24 10:02:06 -07:00

812 lines
14 KiB
LLVM

; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64-unknown-linux-gnu | FileCheck %s
; RUN: llc -verify-machineinstrs < %s -mtriple=powerpc64le-unknown-linux-gnu | FileCheck %s
; Test cases for compare elimination in PPCMIPeephole pass
define void @func1(i32 signext %a) {
; We should have only one compare instruction
; CHECK-LABEL: @func1
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i32 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp slt i32 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func2(i32 signext %a) {
; CHECK-LABEL: @func2
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp slt i32 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i32 %a, 100
br i1 %cmp1, label %if.end3, label %if.then2
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func3(i32 signext %a) {
; CHECK-LABEL: @func3
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp sgt i32 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i32 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func4(i32 zeroext %a) {
; CHECK-LABEL: @func4
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i32 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp ult i32 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func5(i32 zeroext %a) {
; CHECK-LABEL: @func5
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ult i32 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i32 %a, 100
br i1 %cmp1, label %if.end3, label %if.then2
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func6(i32 zeroext %a) {
; CHECK-LABEL: @func6
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ugt i32 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i32 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func7(i64 %a) {
; CHECK-LABEL: @func7
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i64 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp slt i64 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func8(i64 %a) {
; CHECK-LABEL: @func8
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp slt i64 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i64 %a, 100
br i1 %cmp1, label %if.end3, label %if.then2
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func9(i64 %a) {
; CHECK-LABEL: @func9
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp sgt i64 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i64 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func10(i64 %a) {
; CHECK-LABEL: @func10
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i64 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp ult i64 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func11(i64 %a) {
; CHECK-LABEL: @func11
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ult i64 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i64 %a, 100
br i1 %cmp1, label %if.end3, label %if.then2
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func12(i64 %a) {
; CHECK-LABEL: @func12
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ugt i64 %a, 100
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i64 %a, 100
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func13(i32 signext %a, i32 signext %b) {
; CHECK-LABEL: @func13
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp slt i32 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func14(i32 signext %a, i32 signext %b) {
; CHECK-LABEL: @func14
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp slt i32 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp sgt i32 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func15(i32 signext %a, i32 signext %b) {
; CHECK-LABEL: @func15
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp slt i32 %b, %a
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i32 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func16(i32 zeroext %a, i32 zeroext %b) {
; CHECK-LABEL: @func16
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp ult i32 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func17(i32 zeroext %a, i32 zeroext %b) {
; CHECK-LABEL: @func17
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ult i32 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp ugt i32 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func18(i32 zeroext %a, i32 zeroext %b) {
; CHECK-LABEL: @func18
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ult i32 %b, %a
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i32 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func19(i64 %a, i64 %b) {
; CHECK-LABEL: @func19
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i64 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp slt i64 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func20(i64 %a, i64 %b) {
; CHECK-LABEL: @func20
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp slt i64 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp sgt i64 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func21(i64 %a, i64 %b) {
; CHECK-LABEL: @func21
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp slt i64 %b, %a
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i64 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func22(i64 %a, i64 %b) {
; CHECK-LABEL: @func22
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp eq i64 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp ult i64 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func23(i64 %a, i64 %b) {
; CHECK-LABEL: @func23
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ult i64 %a, %b
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp ugt i64 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func24(i64 %a, i64 %b) {
; CHECK-LABEL: @func24
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp ult i64 %b, %a
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i64 %a, %b
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
define void @func25(i64 %a, i64 %b) {
; CHECK-LABEL: @func25
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp slt i64 %b, %a
br i1 %cmp, label %if.then, label %if.else, !prof !1
if.then:
tail call void @dummy1()
br label %if.end6
if.else:
%cmp2 = icmp eq i64 %a, %b
br i1 %cmp2, label %if.then4, label %if.else5
if.then4:
tail call void @dummy2()
br label %if.end6
if.else5:
tail call void @dummy3()
br label %if.end6
if.end6:
ret void
}
define void @func26(i32 signext %a) {
; CHECK-LABEL: @func26
; CHECK: cmp
; CHECK-NOT: cmp
; CHECK: blr
entry:
%cmp = icmp sgt i32 %a, 0
br i1 %cmp, label %if.then, label %if.else, !prof !2
if.then:
tail call void @dummy1()
br label %if.end9
if.else:
%cmp2 = icmp eq i32 %a, 0
br i1 %cmp2, label %if.then7, label %if.else8, !prof !2
if.then7:
tail call void @dummy2()
br label %if.end9
if.else8:
tail call void @dummy3()
br label %if.end9
if.end9:
ret void
}
@g1 = external local_unnamed_addr global i32, align 4
@g2 = external local_unnamed_addr global i32, align 4
define void @func27(i32 signext %a) {
; CHECK-LABEL: @func27
; CHECK: cmp
; CHECK: beq
; CHECK-NOT: cmp
; CHECK: bgelr
; CHECK: blr
entry:
%cmp = icmp eq i32 %a, 0
br i1 %cmp, label %if.end3.sink.split, label %if.else
if.else:
%cmp1 = icmp slt i32 %a, 0
br i1 %cmp1, label %if.end3.sink.split, label %if.end
if.end3.sink.split:
%g2.sink = phi ptr [ @g2, %if.else ], [ @g1, %entry ]
store i32 0, ptr %g2.sink, align 4
br label %if.end
if.end:
ret void
}
; partially redundant case
define void @func28(i32 signext %a) {
; CHECK-LABEL: @func28
; CHECK: cmplwi [[REG1:[0-9]+]], [[REG2:[0-9]+]]
; CHECK: .[[LABEL2:[A-Z0-9_]+]]:
; CHECK: cmpwi [[REG1]], [[REG2]]
; CHECK: ble 0, .[[LABEL1:[A-Z0-9_]+]]
; CHECK-NOT: cmp
; CHECK: bne 0, .[[LABEL2]]
; CHECK: bl dummy1
; CHECK: b .[[LABEL2]]
; CHECK: .[[LABEL1]]:
; CHECK: blr
entry:
br label %do.body
do.body:
%a.addr.0 = phi i32 [ %a, %entry ], [ %call, %if.end ]
%cmp = icmp eq i32 %a.addr.0, 0
br i1 %cmp, label %if.then, label %if.end
if.then:
tail call void @dummy1() #2
br label %if.end
if.end:
%call = tail call signext i32 @func(i32 signext %a.addr.0) #2
%cmp1 = icmp sgt i32 %call, 0
br i1 %cmp1, label %do.body, label %do.end
do.end:
ret void
}
define void @func29(i32 signext %a) {
; We cannot merge two compares due to difference in sign extension behaviors.
; equivalent C code example:
; int a = .. ;
; if (a == -1) dummy1();
; if (a == (uint16_t)-1) dummy2();
; CHECK-LABEL: @func29
; CHECK: cmp
; CHECK: cmp
; CHECK: blr
entry:
%cmp = icmp eq i32 %a, -1
br i1 %cmp, label %if.then, label %if.else
if.then:
tail call void @dummy1()
br label %if.end3
if.else:
%cmp1 = icmp eq i32 %a, 65535
br i1 %cmp1, label %if.then2, label %if.end3
if.then2:
tail call void @dummy2()
br label %if.end3
if.end3:
ret void
}
;; The result of %cmp may change in a tail call. Don't lift %cmp to the entry block.
; CHECK-LABEL: func_tailrecurse:
; CHECK-NOT: cmp
; CHECK: .LBB{{.*}}:
; CHECK: cmplw
; CHECK: blt
define fastcc zeroext i32 @func_tailrecurse(i32 zeroext %a, i32 zeroext %b) {
entry:
br label %tailrecurse
tailrecurse: ; preds = %tailrecurse, %entry
%a.tr = phi i32 [ %a, %entry ], [ %b.tr, %tailrecurse ]
%b.tr = phi i32 [ %b, %entry ], [ %a.tr, %tailrecurse ]
%cmp = icmp ult i32 %a.tr, %b.tr
%conv = zext i1 %cmp to i32
%ignore = call signext i32 (i32) @func(i32 %conv)
br i1 %cmp, label %tailrecurse, label %if.end
if.end: ; preds = %tailrecurse
%sub = sub nsw i32 %a.tr, %b.tr
ret i32 %sub
}
declare void @dummy1()
declare void @dummy2()
declare void @dummy3()
declare signext i32 @func(i32 signext)
!1 = !{!"branch_weights", i32 2000, i32 1}
!2 = !{!"branch_weights", i32 1, i32 2000}