llvm/test/Transforms/InstCombine/adjust-for-minmax.ll
Sanjay Patel fea0530bd5 [InstCombine] canonicalize min/max constant to select's false value
This is a first step towards canonicalization and improved folding/codegen
for integer min/max as discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2016-November/106868.html

Here, we're just matching the simplest min/max patterns and adjusting the
icmp predicate while swapping the select operands.

I've included FIXME tests in test/Transforms/InstCombine/select_meta.ll
so it's easier to see how this might be extended (corresponds to the TODO
comment in the code). That's also why I'm using matchSelectPattern()
rather than a simpler check; once the backend is patched, we can just 
remove some of the restrictions to allow the obfuscated min/max patterns
in the FIXME tests to be matched.

Differential Revision: https://reviews.llvm.org/D26525


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287585 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-21 22:04:14 +00:00

487 lines
15 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -instcombine -S | FileCheck %s
; Instcombine should recognize that this code can be adjusted to fit the canonical max/min pattern.
; No change
define i32 @smax1(i32 %n) {
; CHECK-LABEL: @smax1(
; CHECK-NEXT: [[T:%.*]] = icmp sgt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp sgt i32 %n, 0
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; No change
define i32 @smin1(i32 %n) {
; CHECK-LABEL: @smin1(
; CHECK-NEXT: [[T:%.*]] = icmp slt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp slt i32 %n, 0
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; Canonicalize min/max.
define i32 @smax2(i32 %n) {
; CHECK-LABEL: @smax2(
; CHECK-NEXT: [[T:%.*]] = icmp sgt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp sge i32 %n, 1
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; Canonicalize min/max.
define i32 @smin2(i32 %n) {
; CHECK-LABEL: @smin2(
; CHECK-NEXT: [[T:%.*]] = icmp slt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp sle i32 %n, -1
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; Canonicalize min/max.
define i32 @smax3(i32 %n) {
; CHECK-LABEL: @smax3(
; CHECK-NEXT: [[T:%.*]] = icmp sgt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp sgt i32 %n, -1
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @smax3_vec(<2 x i32> %n) {
; CHECK-LABEL: @smax3_vec(
; CHECK-NEXT: [[T:%.*]] = icmp sgt <2 x i32> %n, zeroinitializer
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp sgt <2 x i32> %n, <i32 -1, i32 -1>
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> zeroinitializer
ret <2 x i32> %m
}
; Canonicalize min/max.
define i32 @smin3(i32 %n) {
; CHECK-LABEL: @smin3(
; CHECK-NEXT: [[T:%.*]] = icmp slt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp slt i32 %n, 1
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @smin3_vec(<2 x i32> %n) {
; CHECK-LABEL: @smin3_vec(
; CHECK-NEXT: [[T:%.*]] = icmp slt <2 x i32> %n, zeroinitializer
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp slt <2 x i32> %n, <i32 1, i32 1>
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> zeroinitializer
ret <2 x i32> %m
}
; Canonicalize min/max.
define i32 @umax3(i32 %n) {
; CHECK-LABEL: @umax3(
; CHECK-NEXT: [[T:%.*]] = icmp ugt i32 %n, 5
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 5
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp ugt i32 %n, 4
%m = select i1 %t, i32 %n, i32 5
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @umax3_vec(<2 x i32> %n) {
; CHECK-LABEL: @umax3_vec(
; CHECK-NEXT: [[T:%.*]] = icmp ugt <2 x i32> %n, <i32 5, i32 5>
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> <i32 5, i32 5>
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp ugt <2 x i32> %n, <i32 4, i32 4>
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> <i32 5, i32 5>
ret <2 x i32> %m
}
; Canonicalize min/max.
define i32 @umin3(i32 %n) {
; CHECK-LABEL: @umin3(
; CHECK-NEXT: [[T:%.*]] = icmp ult i32 %n, 6
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 6
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp ult i32 %n, 7
%m = select i1 %t, i32 %n, i32 6
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @umin3_vec(<2 x i32> %n) {
; CHECK-LABEL: @umin3_vec(
; CHECK-NEXT: [[T:%.*]] = icmp ult <2 x i32> %n, <i32 6, i32 6>
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> <i32 6, i32 6>
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp ult <2 x i32> %n, <i32 7, i32 7>
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> <i32 6, i32 6>
ret <2 x i32> %m
}
; Canonicalize min/max.
define i32 @smax4(i32 %n) {
; CHECK-LABEL: @smax4(
; CHECK-NEXT: [[T:%.*]] = icmp sgt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp sge i32 %n, 0
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @smax4_vec(<2 x i32> %n) {
; CHECK-LABEL: @smax4_vec(
; CHECK-NEXT: [[T:%.*]] = icmp sgt <2 x i32> %n, zeroinitializer
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp sge <2 x i32> %n, zeroinitializer
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> zeroinitializer
ret <2 x i32> %m
}
; Canonicalize min/max.
define i32 @smin4(i32 %n) {
; CHECK-LABEL: @smin4(
; CHECK-NEXT: [[T:%.*]] = icmp slt i32 %n, 0
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 0
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp sle i32 %n, 0
%m = select i1 %t, i32 %n, i32 0
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @smin4_vec(<2 x i32> %n) {
; CHECK-LABEL: @smin4_vec(
; CHECK-NEXT: [[T:%.*]] = icmp slt <2 x i32> %n, zeroinitializer
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> zeroinitializer
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp sle <2 x i32> %n, zeroinitializer
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> zeroinitializer
ret <2 x i32> %m
}
; Canonicalize min/max.
define i32 @umax4(i32 %n) {
; CHECK-LABEL: @umax4(
; CHECK-NEXT: [[T:%.*]] = icmp ugt i32 %n, 8
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 8
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp uge i32 %n, 8
%m = select i1 %t, i32 %n, i32 8
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @umax4_vec(<2 x i32> %n) {
; CHECK-LABEL: @umax4_vec(
; CHECK-NEXT: [[T:%.*]] = icmp ugt <2 x i32> %n, <i32 8, i32 8>
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> <i32 8, i32 8>
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp uge <2 x i32> %n, <i32 8, i32 8>
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> <i32 8, i32 8>
ret <2 x i32> %m
}
; Canonicalize min/max.
define i32 @umin4(i32 %n) {
; CHECK-LABEL: @umin4(
; CHECK-NEXT: [[T:%.*]] = icmp ult i32 %n, 9
; CHECK-NEXT: [[M:%.*]] = select i1 [[T]], i32 %n, i32 9
; CHECK-NEXT: ret i32 [[M]]
;
%t = icmp ule i32 %n, 9
%m = select i1 %t, i32 %n, i32 9
ret i32 %m
}
; Canonicalize min/max.
define <2 x i32> @umin4_vec(<2 x i32> %n) {
; CHECK-LABEL: @umin4_vec(
; CHECK-NEXT: [[T:%.*]] = icmp ult <2 x i32> %n, <i32 9, i32 9>
; CHECK-NEXT: [[M:%.*]] = select <2 x i1> [[T]], <2 x i32> %n, <2 x i32> <i32 9, i32 9>
; CHECK-NEXT: ret <2 x i32> [[M]]
;
%t = icmp ule <2 x i32> %n, <i32 9, i32 9>
%m = select <2 x i1> %t, <2 x i32> %n, <2 x i32> <i32 9, i32 9>
ret <2 x i32> %m
}
define i64 @smax_sext(i32 %a) {
; CHECK-LABEL: @smax_sext(
; CHECK-NEXT: [[A_EXT:%.*]] = sext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i64 [[A_EXT]], 0
; CHECK-NEXT: [[MAX:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 0
; CHECK-NEXT: ret i64 [[MAX]]
;
%a_ext = sext i32 %a to i64
%cmp = icmp sgt i32 %a, -1
%max = select i1 %cmp, i64 %a_ext, i64 0
ret i64 %max
}
define <2 x i64> @smax_sext_vec(<2 x i32> %a) {
; CHECK-LABEL: @smax_sext_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = sext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt <2 x i64> [[A_EXT]], zeroinitializer
; CHECK-NEXT: [[MAX:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> zeroinitializer
; CHECK-NEXT: ret <2 x i64> [[MAX]]
;
%a_ext = sext <2 x i32> %a to <2 x i64>
%cmp = icmp sgt <2 x i32> %a, <i32 -1, i32 -1>
%max = select <2 x i1> %cmp, <2 x i64> %a_ext, <2 x i64> zeroinitializer
ret <2 x i64> %max
}
define i64 @smin_sext(i32 %a) {
; CHECK-LABEL: @smin_sext(
; CHECK-NEXT: [[A_EXT:%.*]] = sext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i64 [[A_EXT]], 0
; CHECK-NEXT: [[MIN:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 0
; CHECK-NEXT: ret i64 [[MIN]]
;
%a_ext = sext i32 %a to i64
%cmp = icmp slt i32 %a, 1
%min = select i1 %cmp, i64 %a_ext, i64 0
ret i64 %min
}
define <2 x i64>@smin_sext_vec(<2 x i32> %a) {
; CHECK-LABEL: @smin_sext_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = sext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i64> [[A_EXT]], zeroinitializer
; CHECK-NEXT: [[MIN:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> zeroinitializer
; CHECK-NEXT: ret <2 x i64> [[MIN]]
;
%a_ext = sext <2 x i32> %a to <2 x i64>
%cmp = icmp slt <2 x i32> %a, <i32 1, i32 1>
%min = select <2 x i1> %cmp, <2 x i64> %a_ext, <2 x i64> zeroinitializer
ret <2 x i64> %min
}
define i64 @umax_sext(i32 %a) {
; CHECK-LABEL: @umax_sext(
; CHECK-NEXT: [[A_EXT:%.*]] = sext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i64 [[A_EXT]], 3
; CHECK-NEXT: [[MAX:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 3
; CHECK-NEXT: ret i64 [[MAX]]
;
%a_ext = sext i32 %a to i64
%cmp = icmp ugt i32 %a, 2
%max = select i1 %cmp, i64 %a_ext, i64 3
ret i64 %max
}
define <2 x i64> @umax_sext_vec(<2 x i32> %a) {
; CHECK-LABEL: @umax_sext_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = sext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i64> [[A_EXT]], <i64 3, i64 3>
; CHECK-NEXT: [[MAX:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> <i64 3, i64 3>
; CHECK-NEXT: ret <2 x i64> [[MAX]]
;
%a_ext = sext <2 x i32> %a to <2 x i64>
%cmp = icmp ugt <2 x i32> %a, <i32 2, i32 2>
%max = select <2 x i1> %cmp, <2 x i64> %a_ext, <2 x i64> <i64 3, i64 3>
ret <2 x i64> %max
}
define i64 @umin_sext(i32 %a) {
; CHECK-LABEL: @umin_sext(
; CHECK-NEXT: [[A_EXT:%.*]] = sext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[A_EXT]], 2
; CHECK-NEXT: [[MIN:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 2
; CHECK-NEXT: ret i64 [[MIN]]
;
%a_ext = sext i32 %a to i64
%cmp = icmp ult i32 %a, 3
%min = select i1 %cmp, i64 %a_ext, i64 2
ret i64 %min
}
define <2 x i64> @umin_sext_vec(<2 x i32> %a) {
; CHECK-LABEL: @umin_sext_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = sext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i64> [[A_EXT]], <i64 2, i64 2>
; CHECK-NEXT: [[MIN:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> <i64 2, i64 2>
; CHECK-NEXT: ret <2 x i64> [[MIN]]
;
%a_ext = sext <2 x i32> %a to <2 x i64>
%cmp = icmp ult <2 x i32> %a, <i32 3, i32 3>
%min = select <2 x i1> %cmp, <2 x i64> %a_ext, <2 x i64> <i64 2, i64 2>
ret <2 x i64> %min
}
define i64 @umax_sext2(i32 %a) {
; CHECK-LABEL: @umax_sext2(
; CHECK-NEXT: [[A_EXT:%.*]] = sext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i64 [[A_EXT]], 2
; CHECK-NEXT: [[MIN:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 2
; CHECK-NEXT: ret i64 [[MIN]]
;
%a_ext = sext i32 %a to i64
%cmp = icmp ult i32 %a, 3
%min = select i1 %cmp, i64 2, i64 %a_ext
ret i64 %min
}
define <2 x i64> @umax_sext2_vec(<2 x i32> %a) {
; CHECK-LABEL: @umax_sext2_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = sext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i64> [[A_EXT]], <i64 2, i64 2>
; CHECK-NEXT: [[MIN:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> <i64 2, i64 2>
; CHECK-NEXT: ret <2 x i64> [[MIN]]
;
%a_ext = sext <2 x i32> %a to <2 x i64>
%cmp = icmp ult <2 x i32> %a, <i32 3, i32 3>
%min = select <2 x i1> %cmp, <2 x i64> <i64 2, i64 2>, <2 x i64> %a_ext
ret <2 x i64> %min
}
define i64 @umin_sext2(i32 %a) {
; CHECK-LABEL: @umin_sext2(
; CHECK-NEXT: [[A_EXT:%.*]] = sext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[A_EXT]], 3
; CHECK-NEXT: [[MIN:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 3
; CHECK-NEXT: ret i64 [[MIN]]
;
%a_ext = sext i32 %a to i64
%cmp = icmp ugt i32 %a, 2
%min = select i1 %cmp, i64 3, i64 %a_ext
ret i64 %min
}
define <2 x i64> @umin_sext2_vec(<2 x i32> %a) {
; CHECK-LABEL: @umin_sext2_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = sext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i64> [[A_EXT]], <i64 3, i64 3>
; CHECK-NEXT: [[MIN:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> <i64 3, i64 3>
; CHECK-NEXT: ret <2 x i64> [[MIN]]
;
%a_ext = sext <2 x i32> %a to <2 x i64>
%cmp = icmp ugt <2 x i32> %a, <i32 2, i32 2>
%min = select <2 x i1> %cmp, <2 x i64> <i64 3, i64 3>, <2 x i64> %a_ext
ret <2 x i64> %min
}
define i64 @umax_zext(i32 %a) {
; CHECK-LABEL: @umax_zext(
; CHECK-NEXT: [[A_EXT:%.*]] = zext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i64 [[A_EXT]], 3
; CHECK-NEXT: [[MAX:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 3
; CHECK-NEXT: ret i64 [[MAX]]
;
%a_ext = zext i32 %a to i64
%cmp = icmp ugt i32 %a, 2
%max = select i1 %cmp, i64 %a_ext, i64 3
ret i64 %max
}
define <2 x i64> @umax_zext_vec(<2 x i32> %a) {
; CHECK-LABEL: @umax_zext_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = zext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i64> [[A_EXT]], <i64 3, i64 3>
; CHECK-NEXT: [[MAX:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> <i64 3, i64 3>
; CHECK-NEXT: ret <2 x i64> [[MAX]]
;
%a_ext = zext <2 x i32> %a to <2 x i64>
%cmp = icmp ugt <2 x i32> %a, <i32 2, i32 2>
%max = select <2 x i1> %cmp, <2 x i64> %a_ext, <2 x i64> <i64 3, i64 3>
ret <2 x i64> %max
}
define i64 @umin_zext(i32 %a) {
; CHECK-LABEL: @umin_zext(
; CHECK-NEXT: [[A_EXT:%.*]] = zext i32 %a to i64
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i64 [[A_EXT]], 2
; CHECK-NEXT: [[MIN:%.*]] = select i1 [[CMP]], i64 [[A_EXT]], i64 2
; CHECK-NEXT: ret i64 [[MIN]]
;
%a_ext = zext i32 %a to i64
%cmp = icmp ult i32 %a, 3
%min = select i1 %cmp, i64 %a_ext, i64 2
ret i64 %min
}
define <2 x i64> @umin_zext_vec(<2 x i32> %a) {
; CHECK-LABEL: @umin_zext_vec(
; CHECK-NEXT: [[A_EXT:%.*]] = zext <2 x i32> %a to <2 x i64>
; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i64> [[A_EXT]], <i64 2, i64 2>
; CHECK-NEXT: [[MIN:%.*]] = select <2 x i1> [[CMP]], <2 x i64> [[A_EXT]], <2 x i64> <i64 2, i64 2>
; CHECK-NEXT: ret <2 x i64> [[MIN]]
;
%a_ext = zext <2 x i32> %a to <2 x i64>
%cmp = icmp ult <2 x i32> %a, <i32 3, i32 3>
%min = select <2 x i1> %cmp, <2 x i64> %a_ext, <2 x i64> <i64 2, i64 2>
ret <2 x i64> %min
}
; Don't crash mishandling a pattern that can't be transformed.
define <2 x i16> @scalar_select_of_vectors(<2 x i16> %a, <2 x i16> %b, i8 %x) {
; CHECK-LABEL: @scalar_select_of_vectors(
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 %x, 0
; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], <2 x i16> %a, <2 x i16> %b
; CHECK-NEXT: ret <2 x i16> [[SEL]]
;
%cmp = icmp slt i8 %x, 0
%sel = select i1 %cmp, <2 x i16> %a, <2 x i16> %b
ret <2 x i16> %sel
}