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llvm-mirror/test/CodeGen/X86/sdiv-exact.ll

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Emit a more efficient magic number multiplication for exact sdivs. We have to do this in DAGBuilder instead of DAGCombiner, because the exact bit is lost after building. struct foo { char x[24]; }; long bar(struct foo *a, struct foo *b) { return a-b; } is now compiled into movl 4(%esp), %eax subl 8(%esp), %eax sarl $3, %eax imull $-1431655765, %eax, %eax instead of movl 4(%esp), %eax subl 8(%esp), %eax movl $715827883, %ecx imull %ecx movl %edx, %eax shrl $31, %eax sarl $2, %edx addl %eax, %edx movl %edx, %eax llvm-svn: 134695
2011-07-08 12:31:30 +02:00
; RUN: llc -march=x86 < %s | FileCheck %s
define i32 @test1(i32 %x) {
%div = sdiv exact i32 %x, 25
ret i32 %div
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:
Emit a more efficient magic number multiplication for exact sdivs. We have to do this in DAGBuilder instead of DAGCombiner, because the exact bit is lost after building. struct foo { char x[24]; }; long bar(struct foo *a, struct foo *b) { return a-b; } is now compiled into movl 4(%esp), %eax subl 8(%esp), %eax sarl $3, %eax imull $-1431655765, %eax, %eax instead of movl 4(%esp), %eax subl 8(%esp), %eax movl $715827883, %ecx imull %ecx movl %edx, %eax shrl $31, %eax sarl $2, %edx addl %eax, %edx movl %edx, %eax llvm-svn: 134695
2011-07-08 12:31:30 +02:00
; CHECK: imull $-1030792151, 4(%esp)
; CHECK-NEXT: ret
}
define i32 @test2(i32 %x) {
%div = sdiv exact i32 %x, 24
ret i32 %div
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:
Emit a more efficient magic number multiplication for exact sdivs. We have to do this in DAGBuilder instead of DAGCombiner, because the exact bit is lost after building. struct foo { char x[24]; }; long bar(struct foo *a, struct foo *b) { return a-b; } is now compiled into movl 4(%esp), %eax subl 8(%esp), %eax sarl $3, %eax imull $-1431655765, %eax, %eax instead of movl 4(%esp), %eax subl 8(%esp), %eax movl $715827883, %ecx imull %ecx movl %edx, %eax shrl $31, %eax sarl $2, %edx addl %eax, %edx movl %edx, %eax llvm-svn: 134695
2011-07-08 12:31:30 +02:00
; CHECK: sarl $3
; CHECK-NEXT: imull $-1431655765
; CHECK-NEXT: ret
}
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