http://llvm.org/bugs/show_bug.cgi?id=10614
Summary: Redundant load of address of array
Product: libraries
Version: trunk
Platform: PC
OS/Version: All
Status: NEW
Severity: normal
Priority: P
Component: Scalar Optimizations
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
The following code produces some a redundant leaq of the address of the array
#include <stdint.h>
static unsigned int const PowersOf10[] =
{0, 1, 10, 100, 1000, 10000, 100000,
1000000, 10000000, 100000000, 1000000000};
uint32_t BiggestPowerTen(uint32_t number,
unsigned int number_bits)
{
unsigned int t = (number_bits);
if (number<PowersOf10[t]) {
t--;
return PowersOf10[t];
} else {
return PowersOf10[t];
}
}
movl %esi, %eax
leaq __ZL10PowersOf10(%rip), %rcx
movl (%rcx,%rax,4), %eax
cmpl %edi, %eax
jbe LBB0_2
decl %esi
leaq __ZL10PowersOf10(%rip), %rax
# we could just reuse $rcx here.
movl (%rax,%rsi,4), %eax
LBB0_2: ## %return
ret
gcc-4.2 does not have this problem.
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