LLVM Bugzilla is read-only and represents the historical archive of all LLVM issues filled before November 26, 2021. Use github to submit LLVM bugs

Bug 17784 - Large constant materialized twice
Summary: Large constant materialized twice
Status: NEW
Alias: None
Product: libraries
Classification: Unclassified
Component: Common Code Generator Code (show other bugs)
Version: trunk
Hardware: PC All
: P normal
Assignee: Unassigned LLVM Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-11-02 13:18 PDT by Rafael Ávila de Espíndola
Modified: 2013-11-04 10:00 PST (History)
2 users (show)

See Also:
Fixed By Commit(s):

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Rafael Ávila de Espíndola 2013-11-02 13:18:06 PDT 
Given

#include <stdint.h>
uint64_t val, *p;
extern uint64_t xtr( uint64_t);

uint64_t caller() {
        uint64_t x;
        p = &val;
        x = 12345123400L;
        *p = x;
        return xtr(x);
}

clang produces

	movq	%rax, (%rcx)
	movabsq	$12345123400, %rcx      ## imm = 0x2DFD3A248
	movq	%rcx, (%rax)
	movabsq	$12345123400, %rdi      ## imm = 0x2DFD3A248


There was a thread about this bug in:

http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-August/064535.html