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authorChris Lattner <sabre@nondot.org>2004-04-06 04:55:43 +0000
committerChris Lattner <sabre@nondot.org>2004-04-06 04:55:43 +0000
commit6c3bf13fceeca60947d7ff2325b3f5fb1bcd5884 (patch)
tree5f22874b3290d015f61871cb2d32782ee6d71507 /llvm/tools/gccld/GenerateCode.cpp
parent1f6024cbbeaf58280fb641c14e942d99c4df21a8 (diff)
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Handle various other important cases of multiplying a long constant immediate. For
example, multiplying X*(1 + (1LL << 32)) now produces: test: mov %ECX, DWORD PTR [%ESP + 4] mov %EDX, DWORD PTR [%ESP + 8] mov %EAX, %ECX add %EDX, %ECX ret [[[Note to Alkis: why isn't linear scan generating this code?? This might be a problem with your intervals being too conservative: test: mov %EAX, DWORD PTR [%ESP + 4] mov %EDX, DWORD PTR [%ESP + 8] add %EDX, %EAX ret end note]]] Whereas GCC produces this: T: sub %esp, 12 mov %edx, DWORD PTR [%esp+16] mov DWORD PTR [%esp+8], %edi mov %ecx, DWORD PTR [%esp+20] xor %edi, %edi mov DWORD PTR [%esp], %ebx mov %ebx, %edi mov %eax, %edx mov DWORD PTR [%esp+4], %esi add %ebx, %edx mov %edi, DWORD PTR [%esp+8] lea %edx, [%ecx+%ebx] mov %esi, DWORD PTR [%esp+4] mov %ebx, DWORD PTR [%esp] add %esp, 12 ret I'm not sure example what GCC is smoking here, but it looks like it has just confused itself with a bunch of stack slots or something. The intel compiler is better, but still not good: T: movl 4(%esp), %edx #2.11 movl 8(%esp), %eax #2.11 lea (%eax,%edx), %ecx #3.12 movl $1, %eax #3.12 mull %edx #3.12 addl %ecx, %edx #3.12 ret #3.12 llvm-svn: 12693
Diffstat (limited to 'llvm/tools/gccld/GenerateCode.cpp')
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