From 150b0bedb7f0aa3af89dbd75a3f046b76260c191 Mon Sep 17 00:00:00 2001 From: Roman Lebedev Date: Sun, 20 Oct 2019 20:51:37 +0000 Subject: [PATCH] [NFC][InstCombine] conditional sign-extend of high-bit-extract: 'and' pat. can be 'or' pattern. In this pattern, all the "magic" bits that we'd add are all high sign bits, and in the value we'd be adding to they are all unset, not unexpectedly, so we can have an `or` there: https://rise4fun.com/Alive/ups git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375377 91177308-0d34-0410-b5e6-96231b3b80d8 --- ...e-length-signext-after-high-bit-extract.ll | 99 +++++++++++++++++++ 1 file changed, 99 insertions(+) diff --git a/test/Transforms/InstCombine/conditional-variable-length-signext-after-high-bit-extract.ll b/test/Transforms/InstCombine/conditional-variable-length-signext-after-high-bit-extract.ll index 027755641e8..3dc1fd244a3 100644 --- a/test/Transforms/InstCombine/conditional-variable-length-signext-after-high-bit-extract.ll +++ b/test/Transforms/InstCombine/conditional-variable-length-signext-after-high-bit-extract.ll @@ -45,6 +45,37 @@ define i32 @t0_notrunc_add(i32 %data, i32 %nbits) { ret i32 %signextended } +define i32 @t0_notrunc_or(i32 %data, i32 %nbits) { +; CHECK-LABEL: @t0_notrunc_or( +; CHECK-NEXT: [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]] +; CHECK-NEXT: [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]] +; CHECK-NEXT: [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0 +; CHECK-NEXT: [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]] +; CHECK-NEXT: [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0 +; CHECK-NEXT: call void @use32(i32 [[LOW_BITS_TO_SKIP]]) +; CHECK-NEXT: call void @use32(i32 [[HIGH_BITS_EXTRACTED]]) +; CHECK-NEXT: call void @use1(i1 [[SHOULD_SIGNEXT]]) +; CHECK-NEXT: call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]]) +; CHECK-NEXT: call void @use32(i32 [[MAGIC]]) +; CHECK-NEXT: [[SIGNEXTENDED:%.*]] = or i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]] +; CHECK-NEXT: ret i32 [[SIGNEXTENDED]] +; + %low_bits_to_skip = sub i32 32, %nbits + %high_bits_extracted = lshr i32 %data, %low_bits_to_skip + %should_signext = icmp slt i32 %data, 0 + %all_bits_except_low_nbits = shl i32 -1, %nbits + %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 + + call void @use32(i32 %low_bits_to_skip) + call void @use32(i32 %high_bits_extracted) + call void @use1(i1 %should_signext) + call void @use32(i32 %all_bits_except_low_nbits) + call void @use32(i32 %magic) + + %signextended = or i32 %high_bits_extracted, %magic + ret i32 %signextended +} + define i32 @t1_notrunc_sub(i32 %data, i32 %nbits) { ; CHECK-LABEL: @t1_notrunc_sub( ; CHECK-NEXT: [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]] @@ -113,6 +144,43 @@ define i32 @t2_trunc_add(i64 %data, i32 %nbits) { ret i32 %signextended } +define i32 @t2_trunc_or(i64 %data, i32 %nbits) { +; CHECK-LABEL: @t2_trunc_or( +; CHECK-NEXT: [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]] +; CHECK-NEXT: [[LOW_BITS_TO_SKIP_WIDE:%.*]] = zext i32 [[LOW_BITS_TO_SKIP]] to i64 +; CHECK-NEXT: [[HIGH_BITS_EXTRACTED_WIDE:%.*]] = lshr i64 [[DATA:%.*]], [[LOW_BITS_TO_SKIP_WIDE]] +; CHECK-NEXT: [[HIGH_BITS_EXTRACTED:%.*]] = trunc i64 [[HIGH_BITS_EXTRACTED_WIDE]] to i32 +; CHECK-NEXT: [[SHOULD_SIGNEXT:%.*]] = icmp slt i64 [[DATA]], 0 +; CHECK-NEXT: [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 -1, [[NBITS]] +; CHECK-NEXT: [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0 +; CHECK-NEXT: call void @use32(i32 [[LOW_BITS_TO_SKIP]]) +; CHECK-NEXT: call void @use64(i64 [[LOW_BITS_TO_SKIP_WIDE]]) +; CHECK-NEXT: call void @use64(i64 [[HIGH_BITS_EXTRACTED_WIDE]]) +; CHECK-NEXT: call void @use32(i32 [[HIGH_BITS_EXTRACTED]]) +; CHECK-NEXT: call void @use1(i1 [[SHOULD_SIGNEXT]]) +; CHECK-NEXT: call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]]) +; CHECK-NEXT: [[SIGNEXTENDED:%.*]] = or i32 [[MAGIC]], [[HIGH_BITS_EXTRACTED]] +; CHECK-NEXT: ret i32 [[SIGNEXTENDED]] +; + %low_bits_to_skip = sub i32 64, %nbits + %low_bits_to_skip_wide = zext i32 %low_bits_to_skip to i64 + %high_bits_extracted_wide = lshr i64 %data, %low_bits_to_skip_wide + %high_bits_extracted = trunc i64 %high_bits_extracted_wide to i32 + %should_signext = icmp slt i64 %data, 0 + %all_bits_except_low_nbits = shl i32 -1, %nbits + %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 ; one-use + + call void @use32(i32 %low_bits_to_skip) + call void @use64(i64 %low_bits_to_skip_wide) + call void @use64(i64 %high_bits_extracted_wide) + call void @use32(i32 %high_bits_extracted) + call void @use1(i1 %should_signext) + call void @use32(i32 %all_bits_except_low_nbits) + + %signextended = or i32 %magic, %high_bits_extracted + ret i32 %signextended +} + define i32 @t3_trunc_sub(i64 %data, i32 %nbits) { ; CHECK-LABEL: @t3_trunc_sub( ; CHECK-NEXT: [[LOW_BITS_TO_SKIP:%.*]] = sub i32 64, [[NBITS:%.*]] @@ -1038,3 +1106,34 @@ define i32 @n28_sub_sext_of_magic(i32 %data, i8 %nbits) { %signextended = sub i32 %high_bits_extracted, %magic_wide ret i32 %signextended } + +define i32 @n290_or_with_wrong_magic(i32 %data, i32 %nbits) { +; CHECK-LABEL: @n290_or_with_wrong_magic( +; CHECK-NEXT: [[LOW_BITS_TO_SKIP:%.*]] = sub i32 32, [[NBITS:%.*]] +; CHECK-NEXT: [[HIGH_BITS_EXTRACTED:%.*]] = lshr i32 [[DATA:%.*]], [[LOW_BITS_TO_SKIP]] +; CHECK-NEXT: [[SHOULD_SIGNEXT:%.*]] = icmp slt i32 [[DATA]], 0 +; CHECK-NEXT: [[ALL_BITS_EXCEPT_LOW_NBITS:%.*]] = shl i32 1, [[NBITS]] +; CHECK-NEXT: [[MAGIC:%.*]] = select i1 [[SHOULD_SIGNEXT]], i32 [[ALL_BITS_EXCEPT_LOW_NBITS]], i32 0 +; CHECK-NEXT: call void @use32(i32 [[LOW_BITS_TO_SKIP]]) +; CHECK-NEXT: call void @use32(i32 [[HIGH_BITS_EXTRACTED]]) +; CHECK-NEXT: call void @use1(i1 [[SHOULD_SIGNEXT]]) +; CHECK-NEXT: call void @use32(i32 [[ALL_BITS_EXCEPT_LOW_NBITS]]) +; CHECK-NEXT: call void @use32(i32 [[MAGIC]]) +; CHECK-NEXT: [[SIGNEXTENDED:%.*]] = or i32 [[HIGH_BITS_EXTRACTED]], [[MAGIC]] +; CHECK-NEXT: ret i32 [[SIGNEXTENDED]] +; + %low_bits_to_skip = sub i32 32, %nbits + %high_bits_extracted = lshr i32 %data, %low_bits_to_skip + %should_signext = icmp slt i32 %data, 0 + %all_bits_except_low_nbits = shl i32 1, %nbits ; not -1 + %magic = select i1 %should_signext, i32 %all_bits_except_low_nbits, i32 0 + + call void @use32(i32 %low_bits_to_skip) + call void @use32(i32 %high_bits_extracted) + call void @use1(i1 %should_signext) + call void @use32(i32 %all_bits_except_low_nbits) + call void @use32(i32 %magic) + + %signextended = or i32 %high_bits_extracted, %magic + ret i32 %signextended +}