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llvm-mirror/test/Transforms/IndVarSimplify/rewrite-loop-exit-value.ll
Philip Reames eb6ef692fc [IndVars] Extend reasoning about loop invariant exits to non-header blocks
Noticed while glancing through the code for other reasons.  The extension is trivial enough, decided to just do it.

llvm-svn: 360694
2019-05-14 17:20:10 +00:00

162 lines
4.4 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -indvars -instcombine -S < %s | FileCheck %s
;; Test that loop's exit value is rewritten to its initial
;; value from loop preheader
define i32 @test1(i32* %var) {
; CHECK-LABEL: @test1(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[COND:%.*]] = icmp eq i32* [[VAR:%.*]], null
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: header:
; CHECK-NEXT: br i1 [[COND]], label [[LOOP:%.*]], label [[EXIT:%.*]]
; CHECK: loop:
; CHECK-NEXT: br label [[HEADER]]
; CHECK: exit:
; CHECK-NEXT: ret i32 0
;
entry:
%cond = icmp eq i32* %var, null
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %loop]
br i1 %cond, label %loop, label %exit
loop:
%indvar = add i32 %phi_indvar, 1
br label %header
exit:
ret i32 %phi_indvar
}
;; Test that we can not rewrite loop exit value if it's not
;; a phi node (%indvar is an add instruction in this test).
define i32 @test2(i32* %var) {
; CHECK-LABEL: @test2(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[COND:%.*]] = icmp eq i32* [[VAR:%.*]], null
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: header:
; CHECK-NEXT: [[PHI_INDVAR:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INDVAR:%.*]], [[HEADER]] ]
; CHECK-NEXT: [[INDVAR]] = add i32 [[PHI_INDVAR]], 1
; CHECK-NEXT: br i1 [[COND]], label [[HEADER]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: ret i32 [[INDVAR]]
;
entry:
%cond = icmp eq i32* %var, null
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %header]
%indvar = add i32 %phi_indvar, 1
br i1 %cond, label %header, label %exit
exit:
ret i32 %indvar
}
;; Test that we can not rewrite loop exit value if the condition
;; is not in loop header.
define i32 @test3(i32* %var) {
; CHECK-LABEL: @test3(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[COND1:%.*]] = icmp eq i32* [[VAR:%.*]], null
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: header:
; CHECK-NEXT: [[PHI_INDVAR:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INDVAR:%.*]], [[HEADER_BACKEDGE:%.*]] ]
; CHECK-NEXT: [[INDVAR]] = add i32 [[PHI_INDVAR]], 1
; CHECK-NEXT: [[COND2:%.*]] = icmp eq i32 [[INDVAR]], 10
; CHECK-NEXT: br i1 [[COND2]], label [[HEADER_BACKEDGE]], label [[BODY:%.*]]
; CHECK: header.backedge:
; CHECK-NEXT: br label [[HEADER]]
; CHECK: body:
; CHECK-NEXT: br i1 [[COND1]], label [[HEADER_BACKEDGE]], label [[EXIT:%.*]]
; CHECK: exit:
; CHECK-NEXT: ret i32 [[PHI_INDVAR]]
;
entry:
%cond1 = icmp eq i32* %var, null
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %header], [%indvar, %body]
%indvar = add i32 %phi_indvar, 1
%cond2 = icmp eq i32 %indvar, 10
br i1 %cond2, label %header, label %body
body:
br i1 %cond1, label %header, label %exit
exit:
ret i32 %phi_indvar
}
; Multiple exits dominating latch
define i32 @test4(i1 %cond1, i1 %cond2) {
; CHECK-LABEL: @test4(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: header:
; CHECK-NEXT: br i1 [[COND1:%.*]], label [[LOOP:%.*]], label [[EXIT:%.*]]
; CHECK: loop:
; CHECK-NEXT: br i1 [[COND2:%.*]], label [[HEADER]], label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: ret i32 0
;
entry:
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %loop]
br i1 %cond1, label %loop, label %exit
loop:
%indvar = add i32 %phi_indvar, 1
br i1 %cond2, label %header, label %exit
exit:
ret i32 %phi_indvar
}
; A conditionally executed exit.
define i32 @test5(i1* %addr, i1 %cond2) {
; CHECK-LABEL: @test5(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[HEADER:%.*]]
; CHECK: header:
; CHECK-NEXT: [[PHI_INDVAR:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INDVAR:%.*]], [[LOOP:%.*]] ]
; CHECK-NEXT: [[COND1:%.*]] = load volatile i1, i1* [[ADDR:%.*]], align 1
; CHECK-NEXT: br i1 [[COND1]], label [[LOOP]], label [[MAYBE:%.*]]
; CHECK: maybe:
; CHECK-NEXT: br i1 [[COND2:%.*]], label [[LOOP]], label [[EXIT:%.*]]
; CHECK: loop:
; CHECK-NEXT: [[INDVAR]] = add i32 [[PHI_INDVAR]], 1
; CHECK-NEXT: br label [[HEADER]]
; CHECK: exit:
; CHECK-NEXT: ret i32 [[PHI_INDVAR]]
;
entry:
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %loop]
%cond1 = load volatile i1, i1* %addr
br i1 %cond1, label %loop, label %maybe
maybe:
br i1 %cond2, label %loop, label %exit
loop:
%indvar = add i32 %phi_indvar, 1
br label %header
exit:
ret i32 %phi_indvar
}