llvm-6502/test/Transforms/EarlyCSE/basic.ll
Chris Lattner 8e7f0d70c7 Teach EarlyCSE to do trivial CSE of loads and read-only calls.
On 176.gcc, this catches 13090 loads and calls, and increases the
number of simple instructions CSE'd from 29658 to 36208.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122727 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-03 03:18:43 +00:00

78 lines
1.7 KiB
LLVM

; RUN: opt < %s -S -early-cse | FileCheck %s
; CHECK: @test1
define void @test1(i8 %V, i32 *%P) {
%A = bitcast i64 42 to double ;; dead
%B = add i32 4, 19 ;; constant folds
store i32 %B, i32* %P
; CHECK-NEXT: store i32 23, i32* %P
%C = zext i8 %V to i32
%D = zext i8 %V to i32 ;; CSE
volatile store i32 %C, i32* %P
volatile store i32 %D, i32* %P
; CHECK-NEXT: %C = zext i8 %V to i32
; CHECK-NEXT: volatile store i32 %C
; CHECK-NEXT: volatile store i32 %C
%E = add i32 %C, %C
%F = add i32 %C, %C
volatile store i32 %E, i32* %P
volatile store i32 %F, i32* %P
; CHECK-NEXT: %E = add i32 %C, %C
; CHECK-NEXT: volatile store i32 %E
; CHECK-NEXT: volatile store i32 %E
%G = add nuw i32 %C, %C ;; not a CSE with E
volatile store i32 %G, i32* %P
; CHECK-NEXT: %G = add nuw i32 %C, %C
; CHECK-NEXT: volatile store i32 %G
ret void
}
;; Simple load value numbering.
; CHECK: @test2
define i32 @test2(i32 *%P) {
%V1 = load i32* %P
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: ret i32 0
}
;; Cross block load value numbering.
; CHECK: @test3
define i32 @test3(i32 *%P, i1 %Cond) {
%V1 = load i32* %P
br i1 %Cond, label %T, label %F
T:
store i32 4, i32* %P
ret i32 42
F:
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: F:
; CHECK: ret i32 0
}
;; Cross block load value numbering stops when stores happen.
; CHECK: @test4
define i32 @test4(i32 *%P, i1 %Cond) {
%V1 = load i32* %P
br i1 %Cond, label %T, label %F
T:
ret i32 42
F:
; Clobbers V1
store i32 42, i32* %P
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: F:
; CHECK: ret i32 %Diff
}