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llvm-mirror/test/Transforms/IndVarSimplify/pr28935.ll
Sanjoy Das ff44ba6c52 [IndVars] Ignore (s|z)exts that don't extend the induction variable
`IVVisitor::visitCast` used to have the invariant that if the
instruction it was passed was a sext or zext instruction, the result of
the instruction would be wider than the induction variable.  This is no
longer true after rL275037, so this change teaches `IndVarSimplify` s
implementation of `IVVisitor::visitCast` to work with the relaxed
invariant.

A corresponding change to SimplifyIndVar to preserve the said invariant
after rL275037 would also work, but given how `IVVisitor::visitCast` is
spelled (no indication of said invariant), I figured the current fix is
cleaner.

Fixes PR28935.

llvm-svn: 278584
2016-08-13 00:58:31 +00:00

21 lines
489 B
LLVM

; RUN: opt -S -indvars < %s | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
declare i16 @fn1(i16 returned, i64)
define void @fn2() {
; CHECK-LABEL: @fn2(
entry:
br label %for.cond
for.cond:
%f.0 = phi i64 [ undef, %entry ], [ %inc, %for.cond ]
%conv = trunc i64 %f.0 to i16
%call = tail call i16 @fn1(i16 %conv, i64 %f.0)
%conv2 = zext i16 %call to i32
%inc = add nsw i64 %f.0, 1
br label %for.cond
}