[DAGCombiner] Attempt to mask vectors before zero extension instead of after.

For cases where we TRUNCATE and then ZERO_EXTEND to a larger size (often from vector legalization), see if we can mask the source data and then ZERO_EXTEND (instead of after a ANY_EXTEND). This can help avoid having to generate a larger mask, and possibly applying it to several sub-vectors.

(zext (truncate x)) -> (zext (and(x, m))

Includes a minor patch to SystemZ to better recognise 8/16-bit zero extension patterns from RISBG bit-extraction code.

This is the first of a number of minor patches to help improve the conversion of byte masks to clear mask shuffles.

Differential Revision: http://reviews.llvm.org/D11764

llvm-svn: 245160

8 files changed, 94 insertions, 81 deletions

diff --git a/llvm/test/CodeGen/AArch64/arm64-aapcs.ll b/llvm/test/CodeGen/AArch64/arm64-aapcs.ll
index f345acf453d..5d25f66b30e 100644
--- a/llvm/test/CodeGen/AArch64/arm64-aapcs.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-aapcs.ll
@@ -27,12 +27,13 @@ define [2 x i64] @test_i64x2_align(i32, [2 x i64] %arg, i32 %after) {
   ; Check stack slots are 64-bit at all times.
 define void @test_stack_slots([8 x i32], i1 %bool, i8 %char, i16 %short,
                                 i32 %int, i64 %long) {
-  ; Part of last store. Blasted scheduler.
-; CHECK: ldr [[LONG:x[0-9]+]], [sp, #32]
-
   %ext_bool = zext i1 %bool to i64
   store volatile i64 %ext_bool, i64* @var64, align 8
 ; CHECK: ldrb w[[EXT:[0-9]+]], [sp]
+
+  ; Part of last store. Blasted scheduler.
+; CHECK: ldr [[LONG:x[0-9]+]], [sp, #32]
+
 ; CHECK: and x[[EXTED:[0-9]+]], x[[EXT]], #0x1
 ; CHECK: str x[[EXTED]], [{{x[0-9]+}}, :lo12:var64]
 
@@ -63,8 +64,8 @@ define void @test_stack_slots([8 x i32], i1 %bool, i8 %char, i16 %short,
 define void @test_extension(i1 %bool, i8 %char, i16 %short, i32 %int) {
   %ext_bool = zext i1 %bool to i64
   store volatile i64 %ext_bool, i64* @var64
-; CHECK: and [[EXT:x[0-9]+]], x0, #0x1
-; CHECK: str [[EXT]], [{{x[0-9]+}}, :lo12:var64]
+; CHECK: and w[[EXT:[0-9]+]], w0, #0x1
+; CHECK: str x[[EXT]], [{{x[0-9]+}}, :lo12:var64]
 
   %ext_char = sext i8 %char to i64
   store volatile i64 %ext_char, i64* @var64
@@ -73,8 +74,8 @@ define void @test_extension(i1 %bool, i8 %char, i16 %short, i32 %int) {
 
   %ext_short = zext i16 %short to i64
   store volatile i64 %ext_short, i64* @var64
-; CHECK: and [[EXT:x[0-9]+]], x2, #0xffff
-; CHECK: str [[EXT]], [{{x[0-9]+}}, :lo12:var64]
+; CHECK: and w[[EXT:[0-9]+]], w2, #0xffff
+; CHECK: str x[[EXT]], [{{x[0-9]+}}, :lo12:var64]
 
   %ext_int = zext i32 %int to i64
   store volatile i64 %ext_int, i64* @var64
diff --git a/llvm/test/CodeGen/AArch64/arm64-arith.ll b/llvm/test/CodeGen/AArch64/arm64-arith.ll
index f36e706b15d..d5d9a1b9817 100644
--- a/llvm/test/CodeGen/AArch64/arm64-arith.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-arith.ll
@@ -123,7 +123,8 @@ entry:
 define i64 @t14(i16 %a, i64 %x) nounwind ssp {
 entry:
 ; CHECK-LABEL: t14:
-; CHECK: add	x0, x1, w0, uxth #3
+; CHECK: and	w8, w0, #0xffff
+; CHECK: add	x0, x1, w8, uxtw #3
 ; CHECK: ret
   %c = zext i16 %a to i64
   %d = shl i64 %c, 3
diff --git a/llvm/test/CodeGen/AArch64/arm64-vector-ext.ll b/llvm/test/CodeGen/AArch64/arm64-vector-ext.ll
index 5bee1611e6c..994a9956cf7 100644
--- a/llvm/test/CodeGen/AArch64/arm64-vector-ext.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-vector-ext.ll
@@ -1,27 +1,27 @@
-; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=apple | FileCheck %s
-
-;CHECK: @func30
-;CHECK: ushll.4s  v0, v0, #0
-;CHECK: movi.4s v1, #0x1
-;CHECK: and.16b v0, v0, v1
-;CHECK: str  q0, [x0]
-;CHECK: ret
-
-%T0_30 = type <4 x i1>
-%T1_30 = type <4 x i32>
-define void @func30(%T0_30 %v0, %T1_30* %p1) {
-  %r = zext %T0_30 %v0 to %T1_30
-  store %T1_30 %r, %T1_30* %p1
-  ret void
-}
-
-; Extend from v1i1 was crashing things (PR20791). Make sure we do something
-; sensible instead.
-define <1 x i32> @autogen_SD7918() {
-; CHECK-LABEL: autogen_SD7918
-; CHECK: movi d0, #0000000000000000
-; CHECK-NEXT: ret
-  %I29 = insertelement <1 x i1> zeroinitializer, i1 false, i32 0
-  %ZE = zext <1 x i1> %I29 to <1 x i32>
-  ret <1 x i32> %ZE
-}
+; RUN: llc < %s -march=arm64 -aarch64-neon-syntax=apple | FileCheck %s

+

+;CHECK: @func30

+;CHECK: movi.4h v1, #0x1

+;CHECK: and.8b v0, v0, v1

+;CHECK: ushll.4s  v0, v0, #0

+;CHECK: str  q0, [x0]

+;CHECK: ret

+

+%T0_30 = type <4 x i1>

+%T1_30 = type <4 x i32>

+define void @func30(%T0_30 %v0, %T1_30* %p1) {

+  %r = zext %T0_30 %v0 to %T1_30

+  store %T1_30 %r, %T1_30* %p1

+  ret void

+}

+

+; Extend from v1i1 was crashing things (PR20791). Make sure we do something

+; sensible instead.

+define <1 x i32> @autogen_SD7918() {

+; CHECK-LABEL: autogen_SD7918

+; CHECK: movi d0, #0000000000000000

+; CHECK-NEXT: ret

+  %I29 = insertelement <1 x i1> zeroinitializer, i1 false, i32 0

+  %ZE = zext <1 x i1> %I29 to <1 x i32>

+  ret <1 x i32> %ZE

+}

diff --git a/llvm/test/CodeGen/AArch64/bitfield.ll b/llvm/test/CodeGen/AArch64/bitfield.ll
index e1e4f62f662..5f19b6943b8 100644
--- a/llvm/test/CodeGen/AArch64/bitfield.ll
+++ b/llvm/test/CodeGen/AArch64/bitfield.ll
@@ -3,51 +3,67 @@
 @var32 = global i32 0
 @var64 = global i64 0
 
-define void @test_extendb(i8 %var) {
-; CHECK-LABEL: test_extendb:
+define void @test_extendb32(i8 %var) {
+; CHECK-LABEL: test_extendb32:
 
   %sxt32 = sext i8 %var to i32
   store volatile i32 %sxt32, i32* @var32
 ; CHECK: sxtb {{w[0-9]+}}, {{w[0-9]+}}
 
-  %sxt64 = sext i8 %var to i64
-  store volatile i64 %sxt64, i64* @var64
-; CHECK: sxtb {{x[0-9]+}}, {{w[0-9]+}}
-
 ; N.b. this doesn't actually produce a bitfield instruction at the
 ; moment, but it's still a good test to have and the semantics are
 ; correct.
   %uxt32 = zext i8 %var to i32
   store volatile i32 %uxt32, i32* @var32
 ; CHECK: and {{w[0-9]+}}, {{w[0-9]+}}, #0xff
+  ret void
+}
+
+define void @test_extendb64(i8 %var) {
+; CHECK-LABEL: test_extendb64:
+
+  %sxt64 = sext i8 %var to i64
+  store volatile i64 %sxt64, i64* @var64
+; CHECK: sxtb {{x[0-9]+}}, {{w[0-9]+}}
 
+; N.b. this doesn't actually produce a bitfield instruction at the
+; moment, but it's still a good test to have and the semantics are
+; correct.
   %uxt64 = zext i8 %var to i64
   store volatile i64 %uxt64, i64* @var64
-; CHECK: and {{x[0-9]+}}, {{x[0-9]+}}, #0xff
+; CHECK: and {{w[0-9]+}}, {{w[0-9]+}}, #0xff
   ret void
 }
 
-define void @test_extendh(i16 %var) {
-; CHECK-LABEL: test_extendh:
+define void @test_extendh32(i16 %var) {
+; CHECK-LABEL: test_extendh32:
 
   %sxt32 = sext i16 %var to i32
   store volatile i32 %sxt32, i32* @var32
 ; CHECK: sxth {{w[0-9]+}}, {{w[0-9]+}}
 
-  %sxt64 = sext i16 %var to i64
-  store volatile i64 %sxt64, i64* @var64
-; CHECK: sxth {{x[0-9]+}}, {{w[0-9]+}}
-
 ; N.b. this doesn't actually produce a bitfield instruction at the
 ; moment, but it's still a good test to have and the semantics are
 ; correct.
   %uxt32 = zext i16 %var to i32
   store volatile i32 %uxt32, i32* @var32
 ; CHECK: and {{w[0-9]+}}, {{w[0-9]+}}, #0xffff
+  ret void
+}
+
+define void @test_extendh64(i16 %var) {
+; CHECK-LABEL: test_extendh64:
+
+  %sxt64 = sext i16 %var to i64
+  store volatile i64 %sxt64, i64* @var64
+; CHECK: sxth {{x[0-9]+}}, {{w[0-9]+}}
 
+; N.b. this doesn't actually produce a bitfield instruction at the
+; moment, but it's still a good test to have and the semantics are
+; correct.
   %uxt64 = zext i16 %var to i64
   store volatile i64 %uxt64, i64* @var64
-; CHECK: and {{x[0-9]+}}, {{x[0-9]+}}, #0xffff
+; CHECK: and {{w[0-9]+}}, {{w[0-9]+}}, #0xffff
   ret void
 }
 
diff --git a/llvm/test/CodeGen/SystemZ/insert-05.ll b/llvm/test/CodeGen/SystemZ/insert-05.ll
index b76859a568f..1ea8a64e28e 100644
--- a/llvm/test/CodeGen/SystemZ/insert-05.ll
+++ b/llvm/test/CodeGen/SystemZ/insert-05.ll
@@ -214,8 +214,8 @@ define i64 @f18(i32 %a) {
 ; The truncation here isn't free; we need an explicit zero extension.
 define i64 @f19(i32 %a) {
 ; CHECK-LABEL: f19:
-; CHECK: llgcr %r2, %r2
-; CHECK: oihl %r2, 1
+; CHECK: llcr %r2, %r2
+; CHECK: iihf %r2, 1
 ; CHECK: br %r14
   %trunc = trunc i32 %a to i8
   %ext = zext i8 %trunc to i64
diff --git a/llvm/test/CodeGen/X86/avx2-conversions.ll b/llvm/test/CodeGen/X86/avx2-conversions.ll
index f97a8ff69ee..402e2e04e62 100644
--- a/llvm/test/CodeGen/X86/avx2-conversions.ll
+++ b/llvm/test/CodeGen/X86/avx2-conversions.ll
@@ -61,8 +61,8 @@ define <8 x i32> @zext8(<8 x i16> %A) nounwind {
 define <8 x i32> @zext_8i8_8i32(<8 x i8> %A) nounwind {
 ; CHECK-LABEL: zext_8i8_8i32:
 ; CHECK:       ## BB#0:
+; CHECK-NEXT:    vpand {{.*}}(%rip), %xmm0, %xmm0
 ; CHECK-NEXT:    vpmovzxwd {{.*#+}} ymm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero,xmm0[4],zero,xmm0[5],zero,xmm0[6],zero,xmm0[7],zero
-; CHECK-NEXT:    vpand {{.*}}(%rip), %ymm0, %ymm0
 ; CHECK-NEXT:    retq
   %B = zext <8 x i8> %A to <8 x i32>
   ret <8 x i32>%B
diff --git a/llvm/test/CodeGen/X86/vec_cast2.ll b/llvm/test/CodeGen/X86/vec_cast2.ll
index 7c039bc9850..311c7870b4b 100644
--- a/llvm/test/CodeGen/X86/vec_cast2.ll
+++ b/llvm/test/CodeGen/X86/vec_cast2.ll
@@ -46,11 +46,10 @@ define <4 x float> @foo1_4(<4 x i8> %src) {
 define <8 x float> @foo2_8(<8 x i8> %src) {
 ; CHECK-LABEL: foo2_8:
 ; CHECK:       ## BB#0:
-; CHECK-NEXT:    vpunpckhwd {{.*#+}} xmm1 = xmm0[4,4,5,5,6,6,7,7]
-; CHECK-NEXT:    vmovdqa {{.*#+}} xmm2 = [255,0,0,0,255,0,0,0,255,0,0,0,255,0,0,0]
-; CHECK-NEXT:    vpand %xmm2, %xmm1, %xmm1
+; CHECK-NEXT:    vpand LCPI2_0, %xmm0, %xmm0
+; CHECK-NEXT:    vpxor %xmm1, %xmm1, %xmm1
+; CHECK-NEXT:    vpunpckhwd {{.*#+}} xmm1 = xmm0[4],xmm1[4],xmm0[5],xmm1[5],xmm0[6],xmm1[6],xmm0[7],xmm1[7]
 ; CHECK-NEXT:    vpmovzxwd {{.*#+}} xmm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
-; CHECK-NEXT:    vpand %xmm2, %xmm0, %xmm0
 ; CHECK-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; CHECK-NEXT:    vcvtdq2ps %ymm0, %ymm0
 ; CHECK-NEXT:    retl
diff --git a/llvm/test/CodeGen/X86/vector-zext.ll b/llvm/test/CodeGen/X86/vector-zext.ll
index 04ace30b819..752eef68fbc 100644
--- a/llvm/test/CodeGen/X86/vector-zext.ll
+++ b/llvm/test/CodeGen/X86/vector-zext.ll
@@ -910,50 +910,46 @@ entry:
 define <8 x i32> @zext_8i8_to_8i32(<8 x i8> %z) {
 ; SSE2-LABEL: zext_8i8_to_8i32:
 ; SSE2:       # BB#0: # %entry
-; SSE2-NEXT:    movdqa %xmm0, %xmm2
-; SSE2-NEXT:    punpcklwd {{.*#+}} xmm2 = xmm2[0],xmm0[0],xmm2[1],xmm0[1],xmm2[2],xmm0[2],xmm2[3],xmm0[3]
-; SSE2-NEXT:    movdqa {{.*#+}} xmm1 = [255,0,0,0,255,0,0,0,255,0,0,0,255,0,0,0]
-; SSE2-NEXT:    pand %xmm1, %xmm2
-; SSE2-NEXT:    punpckhwd {{.*#+}} xmm0 = xmm0[4,4,5,5,6,6,7,7]
-; SSE2-NEXT:    pand %xmm0, %xmm1
-; SSE2-NEXT:    movdqa %xmm2, %xmm0
+; SSE2-NEXT:    movdqa %xmm0, %xmm1
+; SSE2-NEXT:    pand {{.*}}(%rip), %xmm1
+; SSE2-NEXT:    pxor %xmm2, %xmm2
+; SSE2-NEXT:    movdqa %xmm1, %xmm0
+; SSE2-NEXT:    punpcklwd {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1],xmm0[2],xmm2[2],xmm0[3],xmm2[3]
+; SSE2-NEXT:    punpckhwd {{.*#+}} xmm1 = xmm1[4],xmm2[4],xmm1[5],xmm2[5],xmm1[6],xmm2[6],xmm1[7],xmm2[7]
 ; SSE2-NEXT:    retq
 ;
 ; SSSE3-LABEL: zext_8i8_to_8i32:
 ; SSSE3:       # BB#0: # %entry
-; SSSE3-NEXT:    movdqa %xmm0, %xmm2
-; SSSE3-NEXT:    punpcklwd {{.*#+}} xmm2 = xmm2[0],xmm0[0],xmm2[1],xmm0[1],xmm2[2],xmm0[2],xmm2[3],xmm0[3]
-; SSSE3-NEXT:    movdqa {{.*#+}} xmm1 = [255,0,0,0,255,0,0,0,255,0,0,0,255,0,0,0]
-; SSSE3-NEXT:    pand %xmm1, %xmm2
-; SSSE3-NEXT:    punpckhwd {{.*#+}} xmm0 = xmm0[4,4,5,5,6,6,7,7]
-; SSSE3-NEXT:    pand %xmm0, %xmm1
-; SSSE3-NEXT:    movdqa %xmm2, %xmm0
+; SSSE3-NEXT:    movdqa %xmm0, %xmm1
+; SSSE3-NEXT:    pand {{.*}}(%rip), %xmm1
+; SSSE3-NEXT:    pxor %xmm2, %xmm2
+; SSSE3-NEXT:    movdqa %xmm1, %xmm0
+; SSSE3-NEXT:    punpcklwd {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1],xmm0[2],xmm2[2],xmm0[3],xmm2[3]
+; SSSE3-NEXT:    punpckhwd {{.*#+}} xmm1 = xmm1[4],xmm2[4],xmm1[5],xmm2[5],xmm1[6],xmm2[6],xmm1[7],xmm2[7]
 ; SSSE3-NEXT:    retq
 ;
 ; SSE41-LABEL: zext_8i8_to_8i32:
 ; SSE41:       # BB#0: # %entry
-; SSE41-NEXT:    pmovzxwd {{.*#+}} xmm2 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
-; SSE41-NEXT:    movdqa {{.*#+}} xmm1 = [255,0,0,0,255,0,0,0,255,0,0,0,255,0,0,0]
-; SSE41-NEXT:    pand %xmm1, %xmm2
-; SSE41-NEXT:    punpckhwd {{.*#+}} xmm0 = xmm0[4,4,5,5,6,6,7,7]
-; SSE41-NEXT:    pand %xmm0, %xmm1
-; SSE41-NEXT:    movdqa %xmm2, %xmm0
+; SSE41-NEXT:    movdqa %xmm0, %xmm1
+; SSE41-NEXT:    pand {{.*}}(%rip), %xmm1
+; SSE41-NEXT:    pxor %xmm2, %xmm2
+; SSE41-NEXT:    pmovzxwd {{.*#+}} xmm0 = xmm1[0],zero,xmm1[1],zero,xmm1[2],zero,xmm1[3],zero
+; SSE41-NEXT:    punpckhwd {{.*#+}} xmm1 = xmm1[4],xmm2[4],xmm1[5],xmm2[5],xmm1[6],xmm2[6],xmm1[7],xmm2[7]
 ; SSE41-NEXT:    retq
 ;
 ; AVX1-LABEL: zext_8i8_to_8i32:
 ; AVX1:       # BB#0: # %entry
-; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm1 = xmm0[4,4,5,5,6,6,7,7]
-; AVX1-NEXT:    vmovdqa {{.*#+}} xmm2 = [255,0,0,0,255,0,0,0,255,0,0,0,255,0,0,0]
-; AVX1-NEXT:    vpand %xmm2, %xmm1, %xmm1
+; AVX1-NEXT:    vpand {{.*}}(%rip), %xmm0, %xmm0
+; AVX1-NEXT:    vpxor %xmm1, %xmm1, %xmm1
+; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm1 = xmm0[4],xmm1[4],xmm0[5],xmm1[5],xmm0[6],xmm1[6],xmm0[7],xmm1[7]
 ; AVX1-NEXT:    vpmovzxwd {{.*#+}} xmm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
-; AVX1-NEXT:    vpand %xmm2, %xmm0, %xmm0
 ; AVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; AVX1-NEXT:    retq
 ;
 ; AVX2-LABEL: zext_8i8_to_8i32:
 ; AVX2:       # BB#0: # %entry
+; AVX2-NEXT:    vpand {{.*}}(%rip), %xmm0, %xmm0
 ; AVX2-NEXT:    vpmovzxwd {{.*#+}} ymm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero,xmm0[4],zero,xmm0[5],zero,xmm0[6],zero,xmm0[7],zero
-; AVX2-NEXT:    vpand {{.*}}(%rip), %ymm0, %ymm0
 ; AVX2-NEXT:    retq
 entry:
   %t = zext <8 x i8> %z to <8 x i32>