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llvm-mirror/test/Transforms/IndVarSimplify/pr25578.ll
Max Kazantsev 55e622cae0 [SimplifyIndVars] Ignore dead users
IndVarSimplify sometimes makes transforms basing on users that are trivially dead. In particular,
if DCE wasn't run before it, there may be a dead `sext/zext` in loop that will trigger widening
transforms, however it makes no sense to do it.

This patch teaches IndVarsSimplify ignore the mist trivial cases of that.

Differential Revision: https://reviews.llvm.org/D47974
Reviewed By: sanjoy

llvm-svn: 334567
2018-06-13 02:25:32 +00:00

49 lines
1.0 KiB
LLVM

; RUN: opt < %s -indvars -S | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
declare void @use(i64 %x)
; CHECK-LABEL: @foo
define void @foo() {
entry:
br label %L1_header
L1_header:
br label %L2_header
; CHECK: L2_header:
; CHECK: %[[INDVAR:.*]] = phi i64
; CHECK: %[[TRUNC:.*]] = trunc i64 %[[INDVAR]] to i32
L2_header:
%i = phi i32 [ 0, %L1_header ], [ %i_next, %L2_latch ]
%i_prom = sext i32 %i to i64
call void @use(i64 %i_prom)
br label %L3_header
L3_header:
br i1 undef, label %L3_latch, label %L2_exiting_1
L3_latch:
br i1 undef, label %L3_header, label %L2_exiting_2
L2_exiting_1:
br i1 undef, label %L2_latch, label %L1_latch
L2_exiting_2:
br i1 undef, label %L2_latch, label %L1_latch
L2_latch:
%i_next = add nsw i32 %i, 1
br label %L2_header
L1_latch:
; CHECK: L1_latch:
; CHECK: %i_lcssa = phi i32 [ %[[TRUNC]], %L2_exiting_1 ], [ %[[TRUNC]], %L2_exiting_2 ]
%i_lcssa = phi i32 [ %i, %L2_exiting_1 ], [ %i, %L2_exiting_2 ]
br i1 undef, label %exit, label %L1_header
exit:
ret void
}