[AArch64][SVE] Precommit tests for VSCALE/SVE CNTx demanded bits

diff --git a/llvm/test/CodeGen/AArch64/vscale-and-sve-cnt-demandedbits.ll b/llvm/test/CodeGen/AArch64/vscale-and-sve-cnt-demandedbits.ll
new file mode 100644 (file)
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--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/vscale-and-sve-cnt-demandedbits.ll
@@ -0,0 +1,250 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=aarch64 -mattr=+sve < %s | FileCheck %s
+
+; This tests that various ands, sexts, and zexts (and other operations)
+; operating on vscale or the SVE count instructions can be eliminated
+; (via demanded bits) due to their known limited range.
+
+; On AArch64 vscale can be at most 16 (for a 2048-bit vector).
+; The counting instructions (sans multiplier) have a value of at most 256
+; (for a 2048-bit vector of i8s).
+
+define i32 @vscale_and_elimination() vscale_range(1,16) {
+; CHECK-LABEL: vscale_and_elimination:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    rdvl x8, #1
+; CHECK-NEXT:    lsr x8, x8, #4
+; CHECK-NEXT:    and w9, w8, #0x1f
+; CHECK-NEXT:    and w8, w8, #0xfffffffc
+; CHECK-NEXT:    add w0, w9, w8
+; CHECK-NEXT:    ret
+  %vscale = call i32 @llvm.vscale.i32()
+  %and_redundant = and i32 %vscale, 31
+  %and_required = and i32 %vscale, 17179869180
+  %result = add i32 %and_redundant, %and_required
+  ret i32 %result
+}
+
+define i64 @cntb_and_elimination() {
+; CHECK-LABEL: cntb_and_elimination:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntb x8
+; CHECK-NEXT:    and x9, x8, #0x1ff
+; CHECK-NEXT:    and x8, x8, #0x3fffffffc
+; CHECK-NEXT:    add x0, x9, x8
+; CHECK-NEXT:    ret
+  %cntb = call i64 @llvm.aarch64.sve.cntb(i32 31)
+  %and_redundant = and i64 %cntb, 511
+  %and_required = and i64 %cntb, 17179869180
+  %result = add i64 %and_redundant, %and_required
+  ret i64 %result
+}
+
+define i64 @cnth_and_elimination() {
+; CHECK-LABEL: cnth_and_elimination:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cnth x8
+; CHECK-NEXT:    and x9, x8, #0x3ff
+; CHECK-NEXT:    and x8, x8, #0x3fffffffc
+; CHECK-NEXT:    add x0, x9, x8
+; CHECK-NEXT:    ret
+  %cnth = call i64 @llvm.aarch64.sve.cnth(i32 31)
+  %and_redundant = and i64 %cnth, 1023
+  %and_required = and i64 %cnth, 17179869180
+  %result = add i64 %and_redundant, %and_required
+  ret i64 %result
+}
+
+define i64 @cntw_and_elimination() {
+; CHECK-LABEL: cntw_and_elimination:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntw x8
+; CHECK-NEXT:    and x9, x8, #0x7f
+; CHECK-NEXT:    and x8, x8, #0x3fffffffc
+; CHECK-NEXT:    add x0, x9, x8
+; CHECK-NEXT:    ret
+  %cntw = call i64 @llvm.aarch64.sve.cntw(i32 31)
+  %and_redundant = and i64 %cntw, 127
+  %and_required = and i64 %cntw, 17179869180
+  %result = add i64 %and_redundant, %and_required
+  ret i64 %result
+}
+
+define i64 @cntd_and_elimination() {
+; CHECK-LABEL: cntd_and_elimination:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntd x8
+; CHECK-NEXT:    and x9, x8, #0x3f
+; CHECK-NEXT:    and x8, x8, #0x3fffffffc
+; CHECK-NEXT:    add x0, x9, x8
+; CHECK-NEXT:    ret
+  %cntd = call i64 @llvm.aarch64.sve.cntd(i32 31)
+  %and_redundant = and i64 %cntd, 63
+  %and_required = and i64 %cntd, 17179869180
+  %result = add i64 %and_redundant, %and_required
+  ret i64 %result
+}
+
+define i64 @vscale_trunc_zext() vscale_range(1,16) {
+; CHECK-LABEL: vscale_trunc_zext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    rdvl x8, #1
+; CHECK-NEXT:    lsr x8, x8, #4
+; CHECK-NEXT:    and x0, x8, #0xffffffff
+; CHECK-NEXT:    ret
+  %vscale = call i32 @llvm.vscale.i32()
+  %zext = zext i32 %vscale to i64
+  ret i64 %zext
+}
+
+define i64 @vscale_trunc_sext() vscale_range(1,16) {
+; CHECK-LABEL: vscale_trunc_sext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    rdvl x8, #1
+; CHECK-NEXT:    lsr x8, x8, #4
+; CHECK-NEXT:    sxtw x0, w8
+; CHECK-NEXT:    ret
+  %vscale = call i32 @llvm.vscale.i32()
+  %sext = sext i32 %vscale to i64
+  ret i64 %sext
+}
+
+define i64 @count_bytes_trunc_zext() {
+; CHECK-LABEL: count_bytes_trunc_zext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntb x8
+; CHECK-NEXT:    and x0, x8, #0xffffffff
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cntb(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %zext = zext i32 %trunc to i64
+  ret i64 %zext
+}
+
+define i64 @count_halfs_trunc_zext() {
+; CHECK-LABEL: count_halfs_trunc_zext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cnth x8
+; CHECK-NEXT:    and x0, x8, #0xffffffff
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cnth(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %zext = zext i32 %trunc to i64
+  ret i64 %zext
+}
+
+define i64 @count_words_trunc_zext() {
+; CHECK-LABEL: count_words_trunc_zext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntw x8
+; CHECK-NEXT:    and x0, x8, #0xffffffff
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cntw(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %zext = zext i32 %trunc to i64
+  ret i64 %zext
+}
+
+define i64 @count_doubles_trunc_zext() {
+; CHECK-LABEL: count_doubles_trunc_zext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntd x8
+; CHECK-NEXT:    and x0, x8, #0xffffffff
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cntd(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %zext = zext i32 %trunc to i64
+  ret i64 %zext
+}
+
+define i64 @count_bytes_trunc_sext() {
+; CHECK-LABEL: count_bytes_trunc_sext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntb x8
+; CHECK-NEXT:    sxtw x0, w8
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cntb(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %sext = sext i32 %trunc to i64
+  ret i64 %sext
+}
+
+define i64 @count_halfs_trunc_sext() {
+; CHECK-LABEL: count_halfs_trunc_sext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cnth x8
+; CHECK-NEXT:    sxtw x0, w8
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cnth(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %sext = sext i32 %trunc to i64
+  ret i64 %sext
+}
+
+define i64 @count_words_trunc_sext() {
+; CHECK-LABEL: count_words_trunc_sext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntw x8
+; CHECK-NEXT:    sxtw x0, w8
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cntw(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %sext = sext i32 %trunc to i64
+  ret i64 %sext
+}
+
+define i64 @count_doubles_trunc_sext() {
+; CHECK-LABEL: count_doubles_trunc_sext:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    cntd x8
+; CHECK-NEXT:    sxtw x0, w8
+; CHECK-NEXT:    ret
+  %cnt = call i64 @llvm.aarch64.sve.cntd(i32 31)
+  %trunc = trunc i64 %cnt to i32
+  %sext = sext i32 %trunc to i64
+  ret i64 %sext
+}
+
+define i32 @vscale_with_multiplier() vscale_range(1,16) {
+; CHECK-LABEL: vscale_with_multiplier:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    rdvl x8, #1
+; CHECK-NEXT:    mov w9, #5
+; CHECK-NEXT:    lsr x8, x8, #4
+; CHECK-NEXT:    mul x8, x8, x9
+; CHECK-NEXT:    and w9, w8, #0x7f
+; CHECK-NEXT:    and w8, w8, #0x3f
+; CHECK-NEXT:    add w0, w9, w8
+; CHECK-NEXT:    ret
+  %vscale = call i32 @llvm.vscale.i32()
+  %mul = mul i32 %vscale, 5
+  %and_redundant = and i32 %mul, 127
+  %and_required = and i32 %mul, 63
+  %result = add i32 %and_redundant, %and_required
+  ret i32 %result
+}
+
+define i32 @vscale_with_negative_multiplier() vscale_range(1,16) {
+; CHECK-LABEL: vscale_with_negative_multiplier:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    rdvl x8, #1
+; CHECK-NEXT:    mov x9, #-5
+; CHECK-NEXT:    lsr x8, x8, #4
+; CHECK-NEXT:    mul x8, x8, x9
+; CHECK-NEXT:    orr w9, w8, #0xffffff80
+; CHECK-NEXT:    and w8, w8, #0xffffffc0
+; CHECK-NEXT:    add w0, w9, w8
+; CHECK-NEXT:    ret
+  %vscale = call i32 @llvm.vscale.i32()
+  %mul = mul i32 %vscale, -5
+  %or_redundant = or i32 %mul, 4294967168
+  %or_required = and i32 %mul, 4294967232
+  %result = add i32 %or_redundant, %or_required
+  ret i32 %result
+}
+
+declare i32 @llvm.vscale.i32()
+declare i64 @llvm.aarch64.sve.cntb(i32 %pattern)
+declare i64 @llvm.aarch64.sve.cnth(i32 %pattern)
+declare i64 @llvm.aarch64.sve.cntw(i32 %pattern)
+declare i64 @llvm.aarch64.sve.cntd(i32 %pattern)