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llvm-mirror/test/Transforms/GVN/PRE/pre-after-rle.ll
John Brawn 96b2d39585 [MemDep] Use PhiValuesAnalysis to improve alias analysis results
This is being done in order to make GVN able to better optimize certain inputs.
MemDep doesn't use PhiValues directly, but does need to notifiy it when things
get invalidated.

Differential Revision: https://reviews.llvm.org/D48489

llvm-svn: 338384
2018-07-31 14:19:29 +00:00

85 lines
2.4 KiB
LLVM

; RUN: opt -gvn -S < %s | FileCheck %s
declare noalias i8* @malloc(i64)
; Detecting that %s is fully redundant should let us detect that %w is partially
; redundant.
define void @fn1(i32** noalias %start, i32* %width, i32 %h) {
; CHECK-LABEL: @fn1
entry:
%call = tail call noalias i8* @malloc(i64 1024)
%call.cast = bitcast i8* %call to i32*
store i32* %call.cast, i32** %start, align 8
br label %preheader
preheader:
%cmp = icmp slt i32 1, %h
br i1 %cmp, label %body, label %exit
; CHECK-LABEL: preheader.body_crit_edge:
; CHECK: load i32, i32* %width, align 8
; CHECK-LABEL: body:
; CHECK-NOT: load i32*, i32** %start, align 8
; CHECK-NOT: load i32, i32* %width, align 8
body:
%j = phi i32 [ 0, %preheader ], [ %j.next, %body ]
%s = load i32*, i32** %start, align 8
%idx = getelementptr inbounds i32, i32* %s, i64 0
store i32 0, i32* %idx, align 4
%j.next = add nuw nsw i32 %j, 1
%w = load i32, i32* %width, align 8
%cmp3 = icmp slt i32 %j.next, %w
br i1 %cmp3, label %body, label %preheader
exit:
ret void
}
; %s is fully redundant but has more than one available value. Detecting that
; %w is partially redundant requires alias analysis that can analyze those
; values.
define void @fn2(i32** noalias %start, i32* %width, i32 %h, i32 %arg) {
; CHECK-LABEL: @fn2
entry:
%call = tail call noalias i8* @malloc(i64 1024)
%call.cast = bitcast i8* %call to i32*
%cmp1 = icmp slt i32 %arg, 0
br i1 %cmp1, label %if, label %else
if:
store i32* %call.cast, i32** %start, align 8
br label %preheader
else:
%gep = getelementptr inbounds i32, i32* %call.cast, i32 %arg
store i32* %gep, i32** %start, align 8
br label %preheader
; CHECK-LABEL: preheader:
; CHECK: %s = phi i32* [ %s, %body ], [ %gep, %else ], [ %call.cast, %if ]
preheader:
%cmp = icmp slt i32 1, %h
br i1 %cmp, label %body, label %exit
; CHECK-LABEL: preheader.body_crit_edge:
; CHECK: load i32, i32* %width, align 8
; CHECK-LABEL: body:
; CHECK-NOT: load i32*, i32** %start, align 8
; CHECK-NOT: load i32, i32* %width, align 8
body:
%j = phi i32 [ 0, %preheader ], [ %j.next, %body ]
%s = load i32*, i32** %start, align 8
%idx = getelementptr inbounds i32, i32* %s, i64 0
store i32 0, i32* %idx, align 4
%j.next = add nuw nsw i32 %j, 1
%w = load i32, i32* %width, align 8
%cmp3 = icmp slt i32 %j.next, %w
br i1 %cmp3, label %body, label %preheader
exit:
ret void
}