61aec18d46
Summary: This patch adds processing of binary operations when the def of operands are in the same block (i.e. local processing). Earlier we bailed out in such cases (the bail out was introduced in rL252032) because LVI at that time was more precise about context at the end of basic blocks, which implied local def and use analysis didn't benefit CVP. Since then we've added support for LVI in presence of assumes and guards. The test cases added show how local def processing in CVP helps adding more information to the ashr, sdiv, srem and add operators. Note: processCmp which suffers from the same problem will be handled in a later patch. Reviewers: philip, apilipenko, SjoerdMeijer, hfinkel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D38766 llvm-svn: 315634
100 lines
2.4 KiB
LLVM
100 lines
2.4 KiB
LLVM
; RUN: opt < %s -correlated-propagation -S | FileCheck %s
|
|
|
|
; CHECK-LABEL: @test1
|
|
define void @test1(i32 %n) {
|
|
entry:
|
|
br label %for.cond
|
|
|
|
for.cond: ; preds = %for.body, %entry
|
|
%a = phi i32 [ %n, %entry ], [ %shr, %for.body ]
|
|
%cmp = icmp sgt i32 %a, 1
|
|
br i1 %cmp, label %for.body, label %for.end
|
|
|
|
for.body: ; preds = %for.cond
|
|
; CHECK: lshr i32 %a, 5
|
|
%shr = ashr i32 %a, 5
|
|
br label %for.cond
|
|
|
|
for.end: ; preds = %for.cond
|
|
ret void
|
|
}
|
|
|
|
;; Negative test to show transform doesn't happen unless n > 0.
|
|
; CHECK-LABEL: @test2
|
|
define void @test2(i32 %n) {
|
|
entry:
|
|
br label %for.cond
|
|
|
|
for.cond: ; preds = %for.body, %entry
|
|
%a = phi i32 [ %n, %entry ], [ %shr, %for.body ]
|
|
%cmp = icmp sgt i32 %a, -2
|
|
br i1 %cmp, label %for.body, label %for.end
|
|
|
|
for.body: ; preds = %for.cond
|
|
; CHECK: ashr i32 %a, 2
|
|
%shr = ashr i32 %a, 2
|
|
br label %for.cond
|
|
|
|
for.end: ; preds = %for.cond
|
|
ret void
|
|
}
|
|
|
|
;; Non looping test case.
|
|
; CHECK-LABEL: @test3
|
|
define void @test3(i32 %n) {
|
|
entry:
|
|
%cmp = icmp sgt i32 %n, 0
|
|
br i1 %cmp, label %bb, label %exit
|
|
|
|
bb:
|
|
; CHECK: lshr exact i32 %n, 4
|
|
%shr = ashr exact i32 %n, 4
|
|
br label %exit
|
|
|
|
exit:
|
|
ret void
|
|
}
|
|
|
|
; looping case where loop has exactly one block
|
|
; at the point of ashr, we know that the operand is always greater than 0,
|
|
; because of the guard before it, so we can transform it to lshr.
|
|
declare void @llvm.experimental.guard(i1,...)
|
|
; CHECK-LABEL: @test4
|
|
define void @test4(i32 %n) {
|
|
entry:
|
|
%cmp = icmp sgt i32 %n, 0
|
|
br i1 %cmp, label %loop, label %exit
|
|
|
|
loop:
|
|
; CHECK: lshr i32 %a, 1
|
|
%a = phi i32 [ %n, %entry ], [ %shr, %loop ]
|
|
%cond = icmp sgt i32 %a, 2
|
|
call void(i1,...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
|
|
%shr = ashr i32 %a, 1
|
|
br i1 %cond, label %loop, label %exit
|
|
|
|
exit:
|
|
ret void
|
|
}
|
|
|
|
; same test as above with assume instead of guard.
|
|
declare void @llvm.assume(i1)
|
|
; CHECK-LABEL: @test5
|
|
define void @test5(i32 %n) {
|
|
entry:
|
|
%cmp = icmp sgt i32 %n, 0
|
|
br i1 %cmp, label %loop, label %exit
|
|
|
|
loop:
|
|
; CHECK: lshr i32 %a, 1
|
|
%a = phi i32 [ %n, %entry ], [ %shr, %loop ]
|
|
%cond = icmp sgt i32 %a, 4
|
|
call void @llvm.assume(i1 %cond)
|
|
%shr = ashr i32 %a, 1
|
|
%loopcond = icmp sgt i32 %shr, 8
|
|
br i1 %loopcond, label %loop, label %exit
|
|
|
|
exit:
|
|
ret void
|
|
}
|