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[InstCombine] Add test cases demonstrating failure to handle (select (icmp eq (and X, C1), 0), Y, (or Y, C2)) when the icmp portion gets turned into a truncate and a signed compare with 0. 

InstCombine has an optimization that recognizes an and with the sign bit of legal type size and turns it into a truncate and compare that checks the sign bit. But the select handling code doesn't recognize this idiom.

llvm-svn: 305338
This commit is contained in:
Craig Topper 2017-06-13 23:30:41 +00:00
parent f51c80559c
commit 82e4c2dfd2
1 changed files with 31 additions and 0 deletions
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31
llvm/test/Transforms/InstCombine/select-with-bitwise-ops.ll
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@ -1,6 +1,8 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s ; RUN: opt < %s -instcombine -S | FileCheck %s
target datalayout = "n8:16:32:64"
define i32 @select_icmp_eq_and_1_0_or_2(i32 %x, i32 %y) { define i32 @select_icmp_eq_and_1_0_or_2(i32 %x, i32 %y) {
; CHECK-LABEL: @select_icmp_eq_and_1_0_or_2( ; CHECK-LABEL: @select_icmp_eq_and_1_0_or_2(
; CHECK-NEXT: [[AND:%.*]] = shl i32 %x, 1 ; CHECK-NEXT: [[AND:%.*]] = shl i32 %x, 1
@ -295,3 +297,32 @@ define i32 @test67(i16 %x) {
ret i32 %3 ret i32 %3
} }
define i32 @test68(i32 %x, i32 %y) {
; CHECK-LABEL: @test68(
; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 [[X:%.*]] to i8
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[TMP1]], -1
; CHECK-NEXT: [[OR:%.*]] = or i32 [[Y:%.*]], 2
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[CMP]], i32 [[Y]], i32 [[OR]]
; CHECK-NEXT: ret i32 [[SELECT]]
;
%and = and i32 %x, 128
%cmp = icmp eq i32 %and, 0
%or = or i32 %y, 2
%select = select i1 %cmp, i32 %y, i32 %or
ret i32 %select
}
define i32 @test69(i32 %x, i32 %y) {
; CHECK-LABEL: @test69(
; CHECK-NEXT: [[TMP1:%.*]] = trunc i32 [[X:%.*]] to i8
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[TMP1]], 0
; CHECK-NEXT: [[OR:%.*]] = or i32 [[Y:%.*]], 2
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[CMP]], i32 [[Y]], i32 [[OR]]
; CHECK-NEXT: ret i32 [[SELECT]]
;
%and = and i32 %x, 128
%cmp = icmp ne i32 %and, 0
%or = or i32 %y, 2
%select = select i1 %cmp, i32 %y, i32 %or
ret i32 %select
}