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[InstCombine] add tests to show potentially missed logic+trunc transforms; NFC 

llvm-svn: 288270
This commit is contained in:
Sanjay Patel 2016-11-30 20:20:49 +00:00
parent ecee86faa1
commit 3d78d3a2ae
1 changed files with 81 additions and 1 deletions
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82
llvm/test/Transforms/InstCombine/narrow.ll
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@ -1,7 +1,9 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
; Eliminating the casts in this testcase (by narrowing the AND operation)
target datalayout = "n8:16:32:64"
; Eliminating the casts in this testcase (by narrowing the AND operation)
; allows instcombine to realize the function always returns false.
define i1 @test1(i32 %A, i32 %B) {
@ -17,3 +19,81 @@ define i1 @test1(i32 %A, i32 %B) {
ret i1 %ELIM3
}
; TODO: The next 6 (3 logic ops * (scalar+vector)) tests show potential cases for narrowing a bitwise logic op.
define i32 @shrink_xor(i64 %a) {
; CHECK-LABEL: @shrink_xor(
; CHECK-NEXT: [[XOR:%.*]] = xor i64 %a, 1
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i64 [[XOR]] to i32
; CHECK-NEXT: ret i32 [[TRUNC]]
;
%xor = xor i64 %a, 1
%trunc = trunc i64 %xor to i32
ret i32 %trunc
}
; Vectors (with splat constants) should get the same transform.
define <2 x i32> @shrink_xor_vec(<2 x i64> %a) {
; CHECK-LABEL: @shrink_xor_vec(
; CHECK-NEXT: [[XOR:%.*]] = xor <2 x i64> %a, <i64 2, i64 2>
; CHECK-NEXT: [[TRUNC:%.*]] = trunc <2 x i64> [[XOR]] to <2 x i32>
; CHECK-NEXT: ret <2 x i32> [[TRUNC]]
;
%xor = xor <2 x i64> %a, <i64 2, i64 2>
%trunc = trunc <2 x i64> %xor to <2 x i32>
ret <2 x i32> %trunc
}
; Source and dest types are not in the datalayout.
define i3 @shrink_or(i6 %a) {
; CHECK-LABEL: @shrink_or(
; CHECK-NEXT: [[OR:%.*]] = or i6 %a, 1
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i6 [[OR]] to i3
; CHECK-NEXT: ret i3 [[TRUNC]]
;
%or = or i6 %a, 33
%trunc = trunc i6 %or to i3
ret i3 %trunc
}
; Vectors (with non-splat constants) should get the same transform.
define <2 x i8> @shrink_or_vec(<2 x i16> %a) {
; CHECK-LABEL: @shrink_or_vec(
; CHECK-NEXT: [[OR:%.*]] = or <2 x i16> %a, <i16 -1, i16 256>
; CHECK-NEXT: [[TRUNC:%.*]] = trunc <2 x i16> [[OR]] to <2 x i8>
; CHECK-NEXT: ret <2 x i8> [[TRUNC]]
;
%or = or <2 x i16> %a, <i16 -1, i16 256>
%trunc = trunc <2 x i16> %or to <2 x i8>
ret <2 x i8> %trunc
}
; We discriminate against weird types?
define i31 @shrink_and(i64 %a) {
; CHECK-LABEL: @shrink_and(
; CHECK-NEXT: [[AND:%.*]] = and i64 %a, 42
; CHECK-NEXT: [[TRUNC:%.*]] = trunc i64 [[AND]] to i31
; CHECK-NEXT: ret i31 [[TRUNC]]
;
%and = and i64 %a, 42
%trunc = trunc i64 %and to i31
ret i31 %trunc
}
; Chop the top of the constant(s) if needed.
define <2 x i32> @shrink_and_vec(<2 x i33> %a) {
; CHECK-LABEL: @shrink_and_vec(
; CHECK-NEXT: [[AND:%.*]] = and <2 x i33> %a, <i33 -4294967296, i33 6>
; CHECK-NEXT: [[TRUNC:%.*]] = trunc <2 x i33> [[AND]] to <2 x i32>
; CHECK-NEXT: ret <2 x i32> [[TRUNC]]
;
%and = and <2 x i33> %a, <i33 4294967296, i33 6>
%trunc = trunc <2 x i33> %and to <2 x i32>
ret <2 x i32> %trunc
}