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|
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; Tests that check our handling of volatile instructions encountered
; when scanning for dependencies
; RUN: opt -basic-aa -gvn -enable-split-backedge-in-load-pre -S < %s | FileCheck %s
; Check that we can bypass a volatile load when searching
; for dependencies of a non-volatile load
define i32 @test1(i32* nocapture %p, i32* nocapture %q) {
; CHECK-LABEL: @test1(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = load volatile i32, i32* [[Q:%.*]], align 4
; CHECK-NEXT: ret i32 0
;
entry:
%x = load i32, i32* %p
load volatile i32, i32* %q
%y = load i32, i32* %p
%add = sub i32 %y, %x
ret i32 %add
}
; We can not value forward if the query instruction is
; volatile, this would be (in effect) removing the volatile load
define i32 @test2(i32* nocapture %p, i32* nocapture %q) {
; CHECK-LABEL: @test2(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[P:%.*]], align 4
; CHECK-NEXT: [[Y:%.*]] = load volatile i32, i32* [[P]], align 4
; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[Y]], [[X]]
; CHECK-NEXT: ret i32 [[ADD]]
;
entry:
%x = load i32, i32* %p
%y = load volatile i32, i32* %p
%add = sub i32 %y, %x
ret i32 %add
}
; If the query instruction is itself volatile, we *cannot*
; reorder it even if p and q are noalias
define i32 @test3(i32* noalias nocapture %p, i32* noalias nocapture %q) {
; CHECK-LABEL: @test3(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[P:%.*]], align 4
; CHECK-NEXT: [[TMP0:%.*]] = load volatile i32, i32* [[Q:%.*]], align 4
; CHECK-NEXT: [[Y:%.*]] = load volatile i32, i32* [[P]], align 4
; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[Y]], [[X]]
; CHECK-NEXT: ret i32 [[ADD]]
;
entry:
%x = load i32, i32* %p
load volatile i32, i32* %q
%y = load volatile i32, i32* %p
%add = sub i32 %y, %x
ret i32 %add
}
; If an encountered instruction is both volatile and ordered,
; we need to use the strictest ordering of either. In this
; case, the ordering prevents forwarding.
define i32 @test4(i32* noalias nocapture %p, i32* noalias nocapture %q) {
; CHECK-LABEL: @test4(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[X:%.*]] = load i32, i32* [[P:%.*]], align 4
; CHECK-NEXT: [[TMP0:%.*]] = load atomic volatile i32, i32* [[Q:%.*]] seq_cst, align 4
; CHECK-NEXT: [[Y:%.*]] = load atomic i32, i32* [[P]] seq_cst, align 4
; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[Y]], [[X]]
; CHECK-NEXT: ret i32 [[ADD]]
;
entry:
%x = load i32, i32* %p
load atomic volatile i32, i32* %q seq_cst, align 4
%y = load atomic i32, i32* %p seq_cst, align 4
%add = sub i32 %y, %x
ret i32 %add
}
; Value forwarding from a volatile load is perfectly legal
define i32 @test5(i32* nocapture %p, i32* nocapture %q) {
; CHECK-LABEL: @test5(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[X:%.*]] = load volatile i32, i32* [[P:%.*]], align 4
; CHECK-NEXT: ret i32 0
;
entry:
%x = load volatile i32, i32* %p
%y = load i32, i32* %p
%add = sub i32 %y, %x
ret i32 %add
}
; Does cross block redundancy elimination work with volatiles?
define i32 @test6(i32* noalias nocapture %p, i32* noalias nocapture %q) {
; CHECK-LABEL: @test6(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[Y1:%.*]] = load i32, i32* [[P:%.*]], align 4
; CHECK-NEXT: call void @use(i32 [[Y1]])
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: header:
; CHECK-NEXT: [[X:%.*]] = load volatile i32, i32* [[Q:%.*]], align 4
; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[Y1]], [[X]]
; CHECK-NEXT: [[CND:%.*]] = icmp eq i32 [[ADD]], 0
; CHECK-NEXT: br i1 [[CND]], label [[EXIT:%.*]], label [[HEADER]]
; CHECK: exit:
; CHECK-NEXT: ret i32 0
;
entry:
%y1 = load i32, i32* %p
call void @use(i32 %y1)
br label %header
header:
%x = load volatile i32, i32* %q
%y = load i32, i32* %p
%add = sub i32 %y, %x
%cnd = icmp eq i32 %add, 0
br i1 %cnd, label %exit, label %header
exit:
ret i32 %add
}
; Does cross block PRE work with volatiles?
define i32 @test7(i1 %c, i32* noalias nocapture %p, i32* noalias nocapture %q) {
; CHECK-LABEL: @test7(
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[C:%.*]], label [[ENTRY_HEADER_CRIT_EDGE:%.*]], label [[SKIP:%.*]]
; CHECK: entry.header_crit_edge:
; CHECK-NEXT: [[Y_PRE:%.*]] = load i32, i32* [[P:%.*]], align 4
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: skip:
; CHECK-NEXT: [[Y1:%.*]] = load i32, i32* [[P]], align 4
; CHECK-NEXT: call void @use(i32 [[Y1]])
; CHECK-NEXT: br label [[HEADER]]
; CHECK: header:
; CHECK-NEXT: [[Y:%.*]] = phi i32 [ [[Y_PRE]], [[ENTRY_HEADER_CRIT_EDGE]] ], [ [[Y]], [[HEADER]] ], [ [[Y1]], [[SKIP]] ]
; CHECK-NEXT: [[X:%.*]] = load volatile i32, i32* [[Q:%.*]], align 4
; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[Y]], [[X]]
; CHECK-NEXT: [[CND:%.*]] = icmp eq i32 [[ADD]], 0
; CHECK-NEXT: br i1 [[CND]], label [[EXIT:%.*]], label [[HEADER]]
; CHECK: exit:
; CHECK-NEXT: ret i32 0
;
entry:
br i1 %c, label %header, label %skip
skip:
%y1 = load i32, i32* %p
call void @use(i32 %y1)
br label %header
header:
%x = load volatile i32, i32* %q
%y = load i32, i32* %p
%add = sub i32 %y, %x
%cnd = icmp eq i32 %add, 0
br i1 %cnd, label %exit, label %header
exit:
ret i32 %add
}
; Another volatile PRE case - two paths through a loop
; load in preheader, one path read only, one not
define i32 @test8(i1 %b, i1 %c, i32* noalias %p, i32* noalias %q) {
; CHECK-LABEL: @test8(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[Y1:%.*]] = load i32, i32* [[P:%.*]], align 4
; CHECK-NEXT: call void @use(i32 [[Y1]])
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: header:
; CHECK-NEXT: [[Y:%.*]] = phi i32 [ [[Y_PRE:%.*]], [[SKIP_HEADER_CRIT_EDGE:%.*]] ], [ [[Y]], [[HEADER]] ], [ [[Y1]], [[ENTRY:%.*]] ]
; CHECK-NEXT: [[X:%.*]] = load volatile i32, i32* [[Q:%.*]], align 4
; CHECK-NEXT: call void @use(i32 [[Y]])
; CHECK-NEXT: br i1 [[B:%.*]], label [[SKIP:%.*]], label [[HEADER]]
; CHECK: skip:
; CHECK-NEXT: call void @clobber(i32* [[P]], i32* [[Q]])
; CHECK-NEXT: br i1 [[C:%.*]], label [[SKIP_HEADER_CRIT_EDGE]], label [[EXIT:%.*]]
; CHECK: skip.header_crit_edge:
; CHECK-NEXT: [[Y_PRE]] = load i32, i32* [[P]], align 4
; CHECK-NEXT: br label [[HEADER]]
; CHECK: exit:
; CHECK-NEXT: [[ADD:%.*]] = sub i32 [[Y]], [[X]]
; CHECK-NEXT: ret i32 [[ADD]]
;
entry:
%y1 = load i32, i32* %p
call void @use(i32 %y1)
br label %header
header:
%x = load volatile i32, i32* %q
%y = load i32, i32* %p
call void @use(i32 %y)
br i1 %b, label %skip, label %header
skip:
; escaping the arguments is explicitly required since we marked
; them noalias
call void @clobber(i32* %p, i32* %q)
br i1 %c, label %header, label %exit
exit:
%add = sub i32 %y, %x
ret i32 %add
}
; This test checks that we don't optimize away instructions that are
; simplified by SimplifyInstruction(), but are not trivially dead.
define i32 @test9(i32* %V) {
; CHECK-LABEL: @test9(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[LOAD:%.*]] = call i32 undef()
; CHECK-NEXT: ret i32 poison
;
entry:
%load = call i32 undef()
ret i32 %load
}
declare void @use(i32) readonly
declare void @clobber(i32* %p, i32* %q)
!0 = !{ i32 0, i32 1 }
|
