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llvm-mirror/test/CodeGen/X86/add-of-carry.ll

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When adding the carry bit to another value on X86, exploit the fact that the carry-materialization (sbbl x, x) sets the registers to 0 or ~0. Combined with two's complement arithmetic, we can fold the intermediate AND and the ADD into a single SUB. This fixes <rdar://problem/8449754>. llvm-svn: 114460
2010-09-21 20:41:19 +02:00
; RUN: llc < %s -march=x86 | FileCheck %s
; <rdar://problem/8449754>
improve the setcc -> setcc_carry optimization to happen more consistently by moving it out of lowering into dag combine. Add some missing patterns for matching away extended versions of setcc_c. llvm-svn: 122201
2010-12-19 23:08:31 +01:00
define i32 @test1(i32 %sum, i32 %x) nounwind readnone ssp {
When adding the carry bit to another value on X86, exploit the fact that the carry-materialization (sbbl x, x) sets the registers to 0 or ~0. Combined with two's complement arithmetic, we can fold the intermediate AND and the ADD into a single SUB. This fixes <rdar://problem/8449754>. llvm-svn: 114460
2010-09-21 20:41:19 +02:00
entry:
Convert CodeGen/*/*.ll tests to use the new CHECK-LABEL for easier debugging. No functionality change and all tests pass after conversion. This was done with the following sed invocation to catch label lines demarking function boundaries: sed -i '' "s/^;\( *\)\([A-Z0-9_]*\):\( *\)test\([A-Za-z0-9_-]*\):\( *\)$/;\1\2-LABEL:\3test\4:\5/g" test/CodeGen/*/*.ll which was written conservatively to avoid false positives rather than false negatives. I scanned through all the changes and everything looks correct. llvm-svn: 186258
2013-07-13 22:38:47 +02:00
; CHECK-LABEL: test1:
X86: Add a bunch of peeps for add and sub of SETB. "b + ((a < b) ? 1 : 0)" compiles into cmpl %esi, %edi adcl $0, %esi instead of cmpl %esi, %edi sbbl %eax, %eax andl $1, %eax addl %esi, %eax This saves a register, a false dependency on %eax (Intel's CPUs still don't ignore it) and it's shorter. llvm-svn: 131070
2011-05-08 20:36:07 +02:00
; CHECK: cmpl %ecx, %eax
When adding the carry bit to another value on X86, exploit the fact that the carry-materialization (sbbl x, x) sets the registers to 0 or ~0. Combined with two's complement arithmetic, we can fold the intermediate AND and the ADD into a single SUB. This fixes <rdar://problem/8449754>. llvm-svn: 114460
2010-09-21 20:41:19 +02:00
; CHECK-NOT: addl
X86: Add a bunch of peeps for add and sub of SETB. "b + ((a < b) ? 1 : 0)" compiles into cmpl %esi, %edi adcl $0, %esi instead of cmpl %esi, %edi sbbl %eax, %eax andl $1, %eax addl %esi, %eax This saves a register, a false dependency on %eax (Intel's CPUs still don't ignore it) and it's shorter. llvm-svn: 131070
2011-05-08 20:36:07 +02:00
; CHECK: adcl $0, %eax
When adding the carry bit to another value on X86, exploit the fact that the carry-materialization (sbbl x, x) sets the registers to 0 or ~0. Combined with two's complement arithmetic, we can fold the intermediate AND and the ADD into a single SUB. This fixes <rdar://problem/8449754>. llvm-svn: 114460
2010-09-21 20:41:19 +02:00
%add4 = add i32 %x, %sum
%cmp = icmp ult i32 %add4, %x
%inc = zext i1 %cmp to i32
%z.0 = add i32 %add4, %inc
ret i32 %z.0
}
improve the setcc -> setcc_carry optimization to happen more consistently by moving it out of lowering into dag combine. Add some missing patterns for matching away extended versions of setcc_c. llvm-svn: 122201
2010-12-19 23:08:31 +01:00
; Instcombine transforms test1 into test2:
Convert CodeGen/*/*.ll tests to use the new CHECK-LABEL for easier debugging. No functionality change and all tests pass after conversion. This was done with the following sed invocation to catch label lines demarking function boundaries: sed -i '' "s/^;\( *\)\([A-Z0-9_]*\):\( *\)test\([A-Za-z0-9_-]*\):\( *\)$/;\1\2-LABEL:\3test\4:\5/g" test/CodeGen/*/*.ll which was written conservatively to avoid false positives rather than false negatives. I scanned through all the changes and everything looks correct. llvm-svn: 186258
2013-07-13 22:38:47 +02:00
; CHECK-LABEL: test2:
improve the setcc -> setcc_carry optimization to happen more consistently by moving it out of lowering into dag combine. Add some missing patterns for matching away extended versions of setcc_c. llvm-svn: 122201
2010-12-19 23:08:31 +01:00
; CHECK: movl
; CHECK-NEXT: addl
X86: Add a bunch of peeps for add and sub of SETB. "b + ((a < b) ? 1 : 0)" compiles into cmpl %esi, %edi adcl $0, %esi instead of cmpl %esi, %edi sbbl %eax, %eax andl $1, %eax addl %esi, %eax This saves a register, a false dependency on %eax (Intel's CPUs still don't ignore it) and it's shorter. llvm-svn: 131070
2011-05-08 20:36:07 +02:00
; CHECK-NEXT: adcl $0
improve the setcc -> setcc_carry optimization to happen more consistently by moving it out of lowering into dag combine. Add some missing patterns for matching away extended versions of setcc_c. llvm-svn: 122201
2010-12-19 23:08:31 +01:00
; CHECK-NEXT: ret
define i32 @test2(i32 %sum, i32 %x) nounwind readnone ssp {
entry:
%uadd = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %x, i32 %sum)
%0 = extractvalue { i32, i1 } %uadd, 0
%cmp = extractvalue { i32, i1 } %uadd, 1
%inc = zext i1 %cmp to i32
%z.0 = add i32 %0, %inc
ret i32 %z.0
}
(For X86) Enhancement to add-carray/sub-borrow (adc/sbb) optimization. The adc/sbb optimization is to able to convert following expression into a single adc/sbb instruction: (ult) ... = x + 1 // where the ult is unsigned-less-than comparison (ult) ... = x - 1 This change is to flip the "x >u y" (i.e. ugt comparison) in order to expose the adc/sbb opportunity. llvm-svn: 167180
2012-11-01 00:11:48 +01:00
; <rdar://problem/12579915>
define i32 @test3(i32 %x, i32 %y, i32 %res) nounwind uwtable readnone ssp {
entry:
%cmp = icmp ugt i32 %x, %y
%dec = sext i1 %cmp to i32
%dec.res = add nsw i32 %dec, %res
ret i32 %dec.res
Convert CodeGen/*/*.ll tests to use the new CHECK-LABEL for easier debugging. No functionality change and all tests pass after conversion. This was done with the following sed invocation to catch label lines demarking function boundaries: sed -i '' "s/^;\( *\)\([A-Z0-9_]*\):\( *\)test\([A-Za-z0-9_-]*\):\( *\)$/;\1\2-LABEL:\3test\4:\5/g" test/CodeGen/*/*.ll which was written conservatively to avoid false positives rather than false negatives. I scanned through all the changes and everything looks correct. llvm-svn: 186258
2013-07-13 22:38:47 +02:00
; CHECK-LABEL: test3:
(For X86) Enhancement to add-carray/sub-borrow (adc/sbb) optimization. The adc/sbb optimization is to able to convert following expression into a single adc/sbb instruction: (ult) ... = x + 1 // where the ult is unsigned-less-than comparison (ult) ... = x - 1 This change is to flip the "x >u y" (i.e. ugt comparison) in order to expose the adc/sbb opportunity. llvm-svn: 167180
2012-11-01 00:11:48 +01:00
; CHECK: cmpl
; CHECK: sbbl
; CHECK: ret
}
improve the setcc -> setcc_carry optimization to happen more consistently by moving it out of lowering into dag combine. Add some missing patterns for matching away extended versions of setcc_c. llvm-svn: 122201
2010-12-19 23:08:31 +01:00
declare { i32, i1 } @llvm.uadd.with.overflow.i32(i32, i32) nounwind readnone
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