[llvm] r373798 - [NFC][InstCombine] Tests for bit test via highest sign-bit extract (w/ trunc) (PR43564)
Roman Lebedev via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 4 15:15:41 PDT 2019
Author: lebedevri
Date: Fri Oct 4 15:15:41 2019
New Revision: 373798
URL: http://llvm.org/viewvc/llvm-project?rev=373798&view=rev
Log:
[NFC][InstCombine] Tests for bit test via highest sign-bit extract (w/ trunc) (PR43564)
https://rise4fun.com/Alive/x5IS
Added:
llvm/trunk/test/Transforms/InstCombine/sign-bit-test-via-right-shifting-all-other-bits.ll
Added: llvm/trunk/test/Transforms/InstCombine/sign-bit-test-via-right-shifting-all-other-bits.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/sign-bit-test-via-right-shifting-all-other-bits.ll?rev=373798&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/sign-bit-test-via-right-shifting-all-other-bits.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/sign-bit-test-via-right-shifting-all-other-bits.ll Fri Oct 4 15:15:41 2019
@@ -0,0 +1,182 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+define i1 @highest_bit_test_via_lshr(i32 %data, i32 %nbits) {
+; CHECK-LABEL: @highest_bit_test_via_lshr(
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp slt i32 [[DATA:%.*]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %num_low_bits_to_skip = sub i32 32, %nbits
+ %high_bits_extracted = lshr i32 %data, %num_low_bits_to_skip
+ %skip_all_bits_till_signbit = sub i32 %nbits, 1
+ %signbit = lshr i32 %high_bits_extracted, %skip_all_bits_till_signbit
+ %isneg = icmp ne i32 %signbit, 0
+ ret i1 %isneg
+}
+
+define i1 @highest_bit_test_via_lshr_with_truncation(i64 %data, i32 %nbits) {
+; CHECK-LABEL: @highest_bit_test_via_lshr_with_truncation(
+; CHECK-NEXT: [[NUM_LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
+; CHECK-NEXT: [[NUM_LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[NUM_LOW_BITS_TO_SKIP]] to i64
+; CHECK-NEXT: [[HIGH_BITS_EXTRACTED:%.*]] = lshr i64 [[DATA:%.*]], [[NUM_LOW_BITS_TO_SKIP_WIDE]]
+; CHECK-NEXT: [[HIGH_BITS_EXTRACTED_NARROW:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED]] to i32
+; CHECK-NEXT: [[SKIP_ALL_BITS_TILL_SIGNBIT:%.*]] = add i32 [[NBITS]], -1
+; CHECK-NEXT: [[SIGNBIT:%.*]] = lshr i32 [[HIGH_BITS_EXTRACTED_NARROW]], [[SKIP_ALL_BITS_TILL_SIGNBIT]]
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp ne i32 [[SIGNBIT]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %num_low_bits_to_skip = sub i32 64, %nbits
+ %num_low_bits_to_skip_wide = zext i32 %num_low_bits_to_skip to i64
+ %high_bits_extracted = lshr i64 %data, %num_low_bits_to_skip_wide
+ %high_bits_extracted_narrow = trunc i64 %high_bits_extracted to i32
+ %skip_all_bits_till_signbit = sub i32 %nbits, 1
+ %signbit = lshr i32 %high_bits_extracted_narrow, %skip_all_bits_till_signbit
+ %isneg = icmp ne i32 %signbit, 0
+ ret i1 %isneg
+}
+
+define i1 @highest_bit_test_via_ashr(i32 %data, i32 %nbits) {
+; CHECK-LABEL: @highest_bit_test_via_ashr(
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp slt i32 [[DATA:%.*]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %num_low_bits_to_skip = sub i32 32, %nbits
+ %high_bits_extracted = ashr i32 %data, %num_low_bits_to_skip
+ %skip_all_bits_till_signbit = sub i32 %nbits, 1
+ %signbit = ashr i32 %high_bits_extracted, %skip_all_bits_till_signbit
+ %isneg = icmp ne i32 %signbit, 0
+ ret i1 %isneg
+}
+
+define i1 @highest_bit_test_via_ashr_with_truncation(i64 %data, i32 %nbits) {
+; CHECK-LABEL: @highest_bit_test_via_ashr_with_truncation(
+; CHECK-NEXT: [[NUM_LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]]
+; CHECK-NEXT: [[NUM_LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[NUM_LOW_BITS_TO_SKIP]] to i64
+; CHECK-NEXT: [[HIGH_BITS_EXTRACTED:%.*]] = ashr i64 [[DATA:%.*]], [[NUM_LOW_BITS_TO_SKIP_WIDE]]
+; CHECK-NEXT: [[HIGH_BITS_EXTRACTED_NARROW:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED]] to i32
+; CHECK-NEXT: [[SKIP_ALL_BITS_TILL_SIGNBIT:%.*]] = add i32 [[NBITS]], -1
+; CHECK-NEXT: [[SIGNBIT:%.*]] = ashr i32 [[HIGH_BITS_EXTRACTED_NARROW]], [[SKIP_ALL_BITS_TILL_SIGNBIT]]
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp ne i32 [[SIGNBIT]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %num_low_bits_to_skip = sub i32 64, %nbits
+ %num_low_bits_to_skip_wide = zext i32 %num_low_bits_to_skip to i64
+ %high_bits_extracted = ashr i64 %data, %num_low_bits_to_skip_wide
+ %high_bits_extracted_narrow = trunc i64 %high_bits_extracted to i32
+ %skip_all_bits_till_signbit = sub i32 %nbits, 1
+ %signbit = ashr i32 %high_bits_extracted_narrow, %skip_all_bits_till_signbit
+ %isneg = icmp ne i32 %signbit, 0
+ ret i1 %isneg
+}
+
+declare void @use32(i32)
+declare void @use64(i64)
+
+define i1 @unsigned_sign_bit_extract(i32 %x) {
+; CHECK-LABEL: @unsigned_sign_bit_extract(
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp slt i32 [[X:%.*]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signbit = lshr i32 %x, 31
+ %isneg = icmp ne i32 %signbit, 0
+ ret i1 %isneg
+}
+define i1 @unsigned_sign_bit_extract_extrause(i32 %x) {
+; CHECK-LABEL: @unsigned_sign_bit_extract_extrause(
+; CHECK-NEXT: [[SIGNBIT:%.*]] = lshr i32 [[X:%.*]], 31
+; CHECK-NEXT: call void @use32(i32 [[SIGNBIT]])
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp ne i32 [[SIGNBIT]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signbit = lshr i32 %x, 31
+ call void @use32(i32 %signbit)
+ %isneg = icmp ne i32 %signbit, 0
+ ret i1 %isneg
+}
+define i1 @unsigned_sign_bit_extract_extrause__ispositive(i32 %x) {
+; CHECK-LABEL: @unsigned_sign_bit_extract_extrause__ispositive(
+; CHECK-NEXT: [[SIGNBIT:%.*]] = lshr i32 [[X:%.*]], 31
+; CHECK-NEXT: call void @use32(i32 [[SIGNBIT]])
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp eq i32 [[SIGNBIT]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signbit = lshr i32 %x, 31
+ call void @use32(i32 %signbit)
+ %isneg = icmp eq i32 %signbit, 0
+ ret i1 %isneg
+}
+define i1 @signed_sign_bit_extract(i32 %x) {
+; CHECK-LABEL: @signed_sign_bit_extract(
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp slt i32 [[X:%.*]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signsmear = ashr i32 %x, 31
+ %isneg = icmp ne i32 %signsmear, 0
+ ret i1 %isneg
+}
+define i1 @signed_sign_bit_extract_extrause(i32 %x) {
+; CHECK-LABEL: @signed_sign_bit_extract_extrause(
+; CHECK-NEXT: [[SIGNSMEAR:%.*]] = ashr i32 [[X:%.*]], 31
+; CHECK-NEXT: call void @use32(i32 [[SIGNSMEAR]])
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp ne i32 [[SIGNSMEAR]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signsmear = ashr i32 %x, 31
+ call void @use32(i32 %signsmear)
+ %isneg = icmp ne i32 %signsmear, 0
+ ret i1 %isneg
+}
+define i1 @unsigned_sign_bit_extract_with_trunc(i64 %x) {
+; CHECK-LABEL: @unsigned_sign_bit_extract_with_trunc(
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp slt i64 [[X:%.*]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signbit = lshr i64 %x, 63
+ %signbit_narrow = trunc i64 %signbit to i32
+ %isneg = icmp ne i32 %signbit_narrow, 0
+ ret i1 %isneg
+}
+define i1 @unsigned_sign_bit_extract_with_trunc_extrause(i64 %x) {
+; CHECK-LABEL: @unsigned_sign_bit_extract_with_trunc_extrause(
+; CHECK-NEXT: [[SIGNBIT:%.*]] = lshr i64 [[X:%.*]], 63
+; CHECK-NEXT: call void @use64(i64 [[SIGNBIT]])
+; CHECK-NEXT: [[SIGNBIT_NARROW:%.*]] = trunc i64 [[SIGNBIT]] to i32
+; CHECK-NEXT: call void @use32(i32 [[SIGNBIT_NARROW]])
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp ne i32 [[SIGNBIT_NARROW]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signbit = lshr i64 %x, 63
+ call void @use64(i64 %signbit)
+ %signbit_narrow = trunc i64 %signbit to i32
+ call void @use32(i32 %signbit_narrow)
+ %isneg = icmp ne i32 %signbit_narrow, 0
+ ret i1 %isneg
+}
+define i1 @signed_sign_bit_extract_trunc(i64 %x) {
+; CHECK-LABEL: @signed_sign_bit_extract_trunc(
+; CHECK-NEXT: [[SIGNSMEAR:%.*]] = ashr i64 [[X:%.*]], 63
+; CHECK-NEXT: [[SIGNSMEAR_NARROW:%.*]] = trunc i64 [[SIGNSMEAR]] to i32
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp ne i32 [[SIGNSMEAR_NARROW]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signsmear = ashr i64 %x, 63
+ %signsmear_narrow = trunc i64 %signsmear to i32
+ %isneg = icmp ne i32 %signsmear_narrow, 0
+ ret i1 %isneg
+}
+define i1 @signed_sign_bit_extract_trunc_extrause(i64 %x) {
+; CHECK-LABEL: @signed_sign_bit_extract_trunc_extrause(
+; CHECK-NEXT: [[SIGNSMEAR:%.*]] = ashr i64 [[X:%.*]], 63
+; CHECK-NEXT: call void @use64(i64 [[SIGNSMEAR]])
+; CHECK-NEXT: [[SIGNSMEAR_NARROW:%.*]] = trunc i64 [[SIGNSMEAR]] to i32
+; CHECK-NEXT: call void @use32(i32 [[SIGNSMEAR_NARROW]])
+; CHECK-NEXT: [[ISNEG:%.*]] = icmp ne i32 [[SIGNSMEAR_NARROW]], 0
+; CHECK-NEXT: ret i1 [[ISNEG]]
+;
+ %signsmear = ashr i64 %x, 63
+ call void @use64(i64 %signsmear)
+ %signsmear_narrow = trunc i64 %signsmear to i32
+ call void @use32(i32 %signsmear_narrow)
+ %isneg = icmp ne i32 %signsmear_narrow, 0
+ ret i1 %isneg
+}
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