X86: Add a couple of target-specific dag combines that turn VSELECTS into psubus if possible.

We match the pattern "x >= y ? x-y : 0" into "subus x, y" and two special cases
if y is a constant. DAGCombiner canonicalizes those so we first have to undo the
canonicalization for those cases. The pattern occurs in gzip when the loop
vectorizer is enabled. Part of PR14613.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170273 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 340 insertions, 0 deletions

diff --git a/test/CodeGen/X86/psubus.ll b/test/CodeGen/X86/psubus.ll
new file mode 100644
index 0000000000..aff4afbd2e
--- /dev/null
+++ b/test/CodeGen/X86/psubus.ll
@@ -0,0 +1,340 @@
+; RUN: llc -mcpu=core2 < %s | FileCheck %s -check-prefix=SSE2
+; RUN: llc -mcpu=corei7-avx < %s | FileCheck %s -check-prefix=AVX1
+; RUN: llc -mcpu=core-avx2 < %s | FileCheck %s -check-prefix=AVX2
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+
+define void @test1(i16* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i16* %head, i64 %index
+  %1 = bitcast i16* %0 to <8 x i16>*
+  %2 = load <8 x i16>* %1, align 2
+  %3 = icmp slt <8 x i16> %2, zeroinitializer
+  %4 = xor <8 x i16> %2, <i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768>
+  %5 = select <8 x i1> %3, <8 x i16> %4, <8 x i16> zeroinitializer
+  store <8 x i16> %5, <8 x i16>* %1, align 2
+  %index.next = add i64 %index, 8
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; SSE2: @test1
+; SSE2: psubusw LCPI0_0(%rip), %xmm0
+
+; AVX1: @test1
+; AVX1: vpsubusw LCPI0_0(%rip), %xmm0, %xmm0
+
+; AVX2: @test1
+; AVX2: vpsubusw LCPI0_0(%rip), %xmm0, %xmm0
+}
+
+define void @test2(i16* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i16* %head, i64 %index
+  %1 = bitcast i16* %0 to <8 x i16>*
+  %2 = load <8 x i16>* %1, align 2
+  %3 = icmp ugt <8 x i16> %2, <i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766>
+  %4 = add <8 x i16> %2, <i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767>
+  %5 = select <8 x i1> %3, <8 x i16> %4, <8 x i16> zeroinitializer
+  store <8 x i16> %5, <8 x i16>* %1, align 2
+  %index.next = add i64 %index, 8
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; SSE2: @test2
+; SSE2: psubusw LCPI1_0(%rip), %xmm0
+
+; AVX1: @test2
+; AVX1: vpsubusw LCPI1_0(%rip), %xmm0, %xmm0
+
+; AVX2: @test2
+; AVX2: vpsubusw LCPI1_0(%rip), %xmm0, %xmm0
+}
+
+define void @test3(i16* nocapture %head, i16 zeroext %w) nounwind {
+vector.ph:
+  %0 = insertelement <8 x i16> undef, i16 %w, i32 0
+  %broadcast15 = shufflevector <8 x i16> %0, <8 x i16> undef, <8 x i32> zeroinitializer
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %1 = getelementptr inbounds i16* %head, i64 %index
+  %2 = bitcast i16* %1 to <8 x i16>*
+  %3 = load <8 x i16>* %2, align 2
+  %4 = icmp ult <8 x i16> %3, %broadcast15
+  %5 = sub <8 x i16> %3, %broadcast15
+  %6 = select <8 x i1> %4, <8 x i16> zeroinitializer, <8 x i16> %5
+  store <8 x i16> %6, <8 x i16>* %2, align 2
+  %index.next = add i64 %index, 8
+  %7 = icmp eq i64 %index.next, 16384
+  br i1 %7, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; SSE2: @test3
+; SSE2: psubusw %xmm0, %xmm1
+
+; AVX1: @test3
+; AVX1: vpsubusw %xmm0, %xmm1, %xmm1
+
+; AVX2: @test3
+; AVX2: vpsubusw %xmm0, %xmm1, %xmm1
+}
+
+define void @test4(i8* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i8* %head, i64 %index
+  %1 = bitcast i8* %0 to <16 x i8>*
+  %2 = load <16 x i8>* %1, align 1
+  %3 = icmp slt <16 x i8> %2, zeroinitializer
+  %4 = xor <16 x i8> %2, <i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128>
+  %5 = select <16 x i1> %3, <16 x i8> %4, <16 x i8> zeroinitializer
+  store <16 x i8> %5, <16 x i8>* %1, align 1
+  %index.next = add i64 %index, 16
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; SSE2: @test4
+; SSE2: psubusb LCPI3_0(%rip), %xmm0
+
+; AVX1: @test4
+; AVX1: vpsubusb LCPI3_0(%rip), %xmm0, %xmm0
+
+; AVX2: @test4
+; AVX2: vpsubusb LCPI3_0(%rip), %xmm0, %xmm0
+}
+
+define void @test5(i8* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i8* %head, i64 %index
+  %1 = bitcast i8* %0 to <16 x i8>*
+  %2 = load <16 x i8>* %1, align 1
+  %3 = icmp ugt <16 x i8> %2, <i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126>
+  %4 = add <16 x i8> %2, <i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127>
+  %5 = select <16 x i1> %3, <16 x i8> %4, <16 x i8> zeroinitializer
+  store <16 x i8> %5, <16 x i8>* %1, align 1
+  %index.next = add i64 %index, 16
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; SSE2: @test5
+; SSE2: psubusb LCPI4_0(%rip), %xmm0
+
+; AVX1: @test5
+; AVX1: vpsubusb LCPI4_0(%rip), %xmm0, %xmm0
+
+; AVX2: @test5
+; AVX2: vpsubusb LCPI4_0(%rip), %xmm0, %xmm0
+}
+
+define void @test6(i8* nocapture %head, i8 zeroext %w) nounwind {
+vector.ph:
+  %0 = insertelement <16 x i8> undef, i8 %w, i32 0
+  %broadcast15 = shufflevector <16 x i8> %0, <16 x i8> undef, <16 x i32> zeroinitializer
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %1 = getelementptr inbounds i8* %head, i64 %index
+  %2 = bitcast i8* %1 to <16 x i8>*
+  %3 = load <16 x i8>* %2, align 1
+  %4 = icmp ult <16 x i8> %3, %broadcast15
+  %5 = sub <16 x i8> %3, %broadcast15
+  %6 = select <16 x i1> %4, <16 x i8> zeroinitializer, <16 x i8> %5
+  store <16 x i8> %6, <16 x i8>* %2, align 1
+  %index.next = add i64 %index, 16
+  %7 = icmp eq i64 %index.next, 16384
+  br i1 %7, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; SSE2: @test6
+; SSE2: psubusb %xmm0, %xmm1
+
+; AVX1: @test6
+; AVX1: vpsubusb %xmm0, %xmm1, %xmm1
+
+; AVX2: @test6
+; AVX2: vpsubusb %xmm0, %xmm1, %xmm1
+}
+
+define void @test7(i16* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i16* %head, i64 %index
+  %1 = bitcast i16* %0 to <16 x i16>*
+  %2 = load <16 x i16>* %1, align 2
+  %3 = icmp slt <16 x i16> %2, zeroinitializer
+  %4 = xor <16 x i16> %2, <i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768, i16 -32768>
+  %5 = select <16 x i1> %3, <16 x i16> %4, <16 x i16> zeroinitializer
+  store <16 x i16> %5, <16 x i16>* %1, align 2
+  %index.next = add i64 %index, 8
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; AVX2: @test7
+; AVX2: vpsubusw LCPI6_0(%rip), %ymm0, %ymm0
+}
+
+define void @test8(i16* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i16* %head, i64 %index
+  %1 = bitcast i16* %0 to <16 x i16>*
+  %2 = load <16 x i16>* %1, align 2
+  %3 = icmp ugt <16 x i16> %2, <i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766, i16 32766>
+  %4 = add <16 x i16> %2, <i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767, i16 -32767>
+  %5 = select <16 x i1> %3, <16 x i16> %4, <16 x i16> zeroinitializer
+  store <16 x i16> %5, <16 x i16>* %1, align 2
+  %index.next = add i64 %index, 8
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; AVX2: @test8
+; AVX2: vpsubusw LCPI7_0(%rip), %ymm0, %ymm0
+}
+
+define void @test9(i16* nocapture %head, i16 zeroext %w) nounwind {
+vector.ph:
+  %0 = insertelement <16 x i16> undef, i16 %w, i32 0
+  %broadcast15 = shufflevector <16 x i16> %0, <16 x i16> undef, <16 x i32> zeroinitializer
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %1 = getelementptr inbounds i16* %head, i64 %index
+  %2 = bitcast i16* %1 to <16 x i16>*
+  %3 = load <16 x i16>* %2, align 2
+  %4 = icmp ult <16 x i16> %3, %broadcast15
+  %5 = sub <16 x i16> %3, %broadcast15
+  %6 = select <16 x i1> %4, <16 x i16> zeroinitializer, <16 x i16> %5
+  store <16 x i16> %6, <16 x i16>* %2, align 2
+  %index.next = add i64 %index, 8
+  %7 = icmp eq i64 %index.next, 16384
+  br i1 %7, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+
+; AVX2: @test9
+; AVX2: vpsubusw %ymm0, %ymm1, %ymm1
+}
+
+define void @test10(i8* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i8* %head, i64 %index
+  %1 = bitcast i8* %0 to <32 x i8>*
+  %2 = load <32 x i8>* %1, align 1
+  %3 = icmp slt <32 x i8> %2, zeroinitializer
+  %4 = xor <32 x i8> %2, <i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128, i8 -128>
+  %5 = select <32 x i1> %3, <32 x i8> %4, <32 x i8> zeroinitializer
+  store <32 x i8> %5, <32 x i8>* %1, align 1
+  %index.next = add i64 %index, 16
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+
+; AVX2: @test10
+; AVX2: vpsubusb LCPI9_0(%rip), %ymm0, %ymm0
+}
+
+define void @test11(i8* nocapture %head) nounwind {
+vector.ph:
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %0 = getelementptr inbounds i8* %head, i64 %index
+  %1 = bitcast i8* %0 to <32 x i8>*
+  %2 = load <32 x i8>* %1, align 1
+  %3 = icmp ugt <32 x i8> %2, <i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126, i8 126>
+  %4 = add <32 x i8> %2, <i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127, i8 -127>
+  %5 = select <32 x i1> %3, <32 x i8> %4, <32 x i8> zeroinitializer
+  store <32 x i8> %5, <32 x i8>* %1, align 1
+  %index.next = add i64 %index, 16
+  %6 = icmp eq i64 %index.next, 16384
+  br i1 %6, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; AVX2: @test11
+; AVX2: vpsubusb LCPI10_0(%rip), %ymm0, %ymm0
+}
+
+define void @test12(i8* nocapture %head, i8 zeroext %w) nounwind {
+vector.ph:
+  %0 = insertelement <32 x i8> undef, i8 %w, i32 0
+  %broadcast15 = shufflevector <32 x i8> %0, <32 x i8> undef, <32 x i32> zeroinitializer
+  br label %vector.body
+
+vector.body:                                      ; preds = %vector.body, %vector.ph
+  %index = phi i64 [ 0, %vector.ph ], [ %index.next, %vector.body ]
+  %1 = getelementptr inbounds i8* %head, i64 %index
+  %2 = bitcast i8* %1 to <32 x i8>*
+  %3 = load <32 x i8>* %2, align 1
+  %4 = icmp ult <32 x i8> %3, %broadcast15
+  %5 = sub <32 x i8> %3, %broadcast15
+  %6 = select <32 x i1> %4, <32 x i8> zeroinitializer, <32 x i8> %5
+  store <32 x i8> %6, <32 x i8>* %2, align 1
+  %index.next = add i64 %index, 16
+  %7 = icmp eq i64 %index.next, 16384
+  br i1 %7, label %for.end, label %vector.body
+
+for.end:                                          ; preds = %vector.body
+  ret void
+
+; AVX2: @test12
+; AVX2: vpsubusb %ymm0, %ymm1, %ymm1
+}