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[NFC][InstCombine] conditional sign-extend of high-bit-extract: 'and' pat. can be 'or' pattern.

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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
This commit is contained in:
Roman Lebedev
2019-10-20 20:51:37 +00:00
parent b7aa2ef391
commit 150b0bedb7
1 changed files with 99 additions and 0 deletions
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test/Transforms/InstCombine/conditional-variable-length-signext-after-high-bit-extract.ll
+99
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@@ -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
}