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[Bug rtl-optimization/50088] movzbl is generated instead of movl
- From: "hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Wed, 17 Aug 2011 14:37:35 +0000
- Subject: [Bug rtl-optimization/50088] movzbl is generated instead of movl
- Auto-submitted: auto-generated
- References: <bug-50088-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50088
--- Comment #16 from H.J. Lu <hjl.tools at gmail dot com> 2011-08-17 14:37:35 UTC ---
The testcase has ...
int n8 = (arr[7] * 9 + 8) & 15;
for (i = 0; i < len; i+=8)
{
n1 = (n1 + 1) & 15;
s += arr[i] << n1;
The shift count is 32bit, which causes 32bit spill. Since shift/rotate
instructions only take 8bit register (CL) as shift count, we load 8bit
into CL. How do we solve this?