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llvm-mirror/test/Analysis/ScalarEvolution/sext-inreg.ll
Justin Lebar 4a161bf875 [SCEV] Simplify trunc-of-add/mul to add/mul-of-trunc under more circumstances.
Summary:
Previously we would do this simplification only if it did not introduce
any new truncs (excepting new truncs which replace other cast ops).

This change weakens this condition: If the number of truncs stays the
same, but we're able to transform trunc(X + Y) to X + trunc(Y), that's
still simpler, and it may open up additional transformations.

While we're here, also clean up some duplicated code.

Reviewers: sanjoy

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D48160

llvm-svn: 334736
2018-06-14 17:13:35 +00:00

36 lines
1.2 KiB
LLVM

; RUN: opt < %s -analyze -scalar-evolution | FileCheck %s
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i386-apple-darwin9.6"
define i64 @foo(i64* nocapture %x, i64 %n) nounwind {
; CHECK-LABEL: Classifying expressions for: @foo
entry:
%t0 = icmp sgt i64 %n, 0
br i1 %t0, label %bb, label %return
bb:
%i.01 = phi i64 [ 0, %entry ], [ %indvar.next, %bb ]
%t1 = shl i64 %i.01, 7
%t2 = ashr i64 %t1, 7
; CHECK: %t2 = ashr i64 %t1, 7
; CHECK-NEXT: sext i57 {0,+,199}<%bb> to i64
; CHECK-SAME: Exits: (sext i57 (-199 + (trunc i64 %n to i57)) to i64)
; CHECK: %s2 = ashr i64 %s1, 5
; CHECK-NEXT: sext i59 {0,+,199}<%bb> to i64
; CHECK-SAME: Exits: (sext i59 (-199 + (trunc i64 %n to i59)) to i64)
%s1 = shl i64 %i.01, 5
%s2 = ashr i64 %s1, 5
%t3 = getelementptr i64, i64* %x, i64 %i.01
store i64 0, i64* %t3, align 1
%indvar.next = add i64 %i.01, 199
%exitcond = icmp eq i64 %indvar.next, %n
br i1 %exitcond, label %return, label %bb
return:
%p = phi i64 [ 0, %entry ], [ %t2, %bb ]
%q = phi i64 [ 0, %entry ], [ %s2, %bb ]
%v = xor i64 %p, %q
ret i64 %v
}